x-y+1=0
5x+y=13
Please show method :)
Solve this maths question?
2015-10-20 7:52 pm
回答 (29)
2015-10-20 8:09 pm
✔ 最佳答案
You should solve the first equation for one variable (say, x) and then substitute that variable intothe second equation.This will allow you to find the value of the other variable (y). This value can
then be substituted back into the original equation to solve for x.
1. Solve first equation for one variable (I chose x).
x - y + 1 = 0
x = y - 1
2. Substitute the value of x into the second equation to solve for y.
5x + y = 13
5(y-1) + y = 13
5y - 5 + y = 13
6y - 5 = 13
6y = 18
y = 3
3. Plug the value of y back into the original equation to solve for x.
x - y + 1 = 0
x - (3) + 1 = 0
x - 2 = 0
x = 2
4. Verify these values in the second equation.
5(2) + (3) = 13
10 + 3 = 13
Check!
5. The answer is x = 2, y = 3
2015-10-20 11:43 pm
Whenever you have these type of situation (simultaneous equations), it really helps by 1st re-arranging the equations.
1) Re-arrange the equations in some kin of an 'order' so that you can either add or subtract all the terms:
x - y = -1
5x + y = 13
you see what I'm getting at? Xs, Ys and numbers in 'column'.
You can start from here but it'll be a LOT easier if you re-arrange again so that you'll have the larger coefficient of x above:
5x + y = 13 (i)
x - y = -1 (ii)
2) The trick is to get rid of something first and you can see that if we *add* (ii) from (i) the Ys go (+y + - y = 0)
So
(5x + x) + (y-y) = (13 - 1)
6x + 0 = 12
6x = 12
x = 12/6
x = 2
3) Now that you've found x (which is 2) simply plug it into either (i) or (ii) but chose the more simple equation of the two, x - y = -1
2 - y = -1
-y = -1 - 2
-y = -3
y = 3
2) Now we need to decide whether to add or subtract BUT
1) Re-arrange the equations in some kin of an 'order' so that you can either add or subtract all the terms:
x - y = -1
5x + y = 13
you see what I'm getting at? Xs, Ys and numbers in 'column'.
You can start from here but it'll be a LOT easier if you re-arrange again so that you'll have the larger coefficient of x above:
5x + y = 13 (i)
x - y = -1 (ii)
2) The trick is to get rid of something first and you can see that if we *add* (ii) from (i) the Ys go (+y + - y = 0)
So
(5x + x) + (y-y) = (13 - 1)
6x + 0 = 12
6x = 12
x = 12/6
x = 2
3) Now that you've found x (which is 2) simply plug it into either (i) or (ii) but chose the more simple equation of the two, x - y = -1
2 - y = -1
-y = -1 - 2
-y = -3
y = 3
2) Now we need to decide whether to add or subtract BUT
2015-10-21 6:53 am
x-y+1=0
5x+y=13
x - y = -1
5x+ y = 13
Add the equations:
6x = 12
x = 2
Substitute this value for 2 in either equation
x-y+1=0
2 - y + 1 = 0
- y + 3 = 0
- y = - 3
y = 3
5x+y=13
x - y = -1
5x+ y = 13
Add the equations:
6x = 12
x = 2
Substitute this value for 2 in either equation
x-y+1=0
2 - y + 1 = 0
- y + 3 = 0
- y = - 3
y = 3
2015-10-22 5:46 am
no?
2015-10-21 9:29 pm
You can choose any method of solving the system equations such as elimination or substitutions method.
Let us apply substitutions method. First you can rewrite x+y+1=0 as x+y=-1
Now you can take x as (-1-y) and then substitute it in the second equation.
You will have 5(-1-y)+y=13
-5-5y+y=13
-4y=13+5
-4y=18
Here, y=-9/2
Use y=-9/2 to substitute into x-y-1=0 to solve for x.
x=y+1
x=-9/2+1
x=-7/2
Let us apply substitutions method. First you can rewrite x+y+1=0 as x+y=-1
Now you can take x as (-1-y) and then substitute it in the second equation.
You will have 5(-1-y)+y=13
-5-5y+y=13
-4y=13+5
-4y=18
Here, y=-9/2
Use y=-9/2 to substitute into x-y-1=0 to solve for x.
x=y+1
x=-9/2+1
x=-7/2
參考: I went to secondary school
2015-10-20 8:04 pm
x-y+1=0 -->(1) 5x+y=13 --->(2) eq(1) ==> x= y-1 --->(3) substitute the value of x in eq(2) 5 (y-1) +y =13 5y-5+y =13 6y =13+5 6y =18 y=3. substitute y=3 in eq(3) x = 3-1 x=2 . hence, x=2 ,y=3
2015-10-20 7:55 pm
x-y+1=0
5x+y=13
x-y=-1
5x+y=13
-----------
6x=12
x=2
2-y=-1
y=3
x=2 y=3
check
x-y+1=0 2-3+1=0
5x+y=13 5(2)+3=13
5x+y=13
x-y=-1
5x+y=13
-----------
6x=12
x=2
2-y=-1
y=3
x=2 y=3
check
x-y+1=0 2-3+1=0
5x+y=13 5(2)+3=13
2015-10-24 5:04 pm
x=2, y=3
2015-10-24 7:24 am
x=2 y=3
2015-10-23 9:47 pm
x - y + 1 = 0
5x + y = 13
5(y - 1) + y = 13
6y = 18
y = 3
x = 2
5x + y = 13
5(y - 1) + y = 13
6y = 18
y = 3
x = 2
2015-10-23 7:48 pm
May GOD bless you
2015-10-23 2:45 pm
x - y + 1 = 0
5x + y = 13
Add the two equations and subtract 1 from each side to get 6x = 12, from which x = 2 and y = 3
5x + y = 13
Add the two equations and subtract 1 from each side to get 6x = 12, from which x = 2 and y = 3
2015-10-23 11:45 am
y = x + 1
y = -5x + 13
x + 1 = -5x + 13
6x = 12
x = 2 => y = 3
y = -5x + 13
x + 1 = -5x + 13
6x = 12
x = 2 => y = 3
2015-10-23 7:24 am
BY substitution
x=2,y=3
x=2,y=3
2015-10-23 6:11 am
x = 2
y = 3
y = 3
2015-10-23 3:42 am
Y=13-5x
Y=X+1
13-5X=X+1
6X=12
X=2
Y=2+1=3
Y=X+1
13-5X=X+1
6X=12
X=2
Y=2+1=3
2015-10-23 1:18 am
x - y = -1 ------------(1)
5 x + y = 13-----------(2)
(1) + (2)
6 x = 12, x = 12/6 x = 2.
Substitute x = 2 in (1)
2 - y = -1
-y = -1-2
-y = -3
y = 3
5 x + y = 13-----------(2)
(1) + (2)
6 x = 12, x = 12/6 x = 2.
Substitute x = 2 in (1)
2 - y = -1
-y = -1-2
-y = -3
y = 3
2015-10-23 1:01 am
42.... all the others have it wrong. Your homework answer is 42
2015-10-22 12:22 pm
x-y+1=0
5x+y=13
x-y = -1
5x+y=13
Mutiply x-y = -1 by (-5), which gives -5x+5y=5
You now have:
-5x+5y=5
5x+y=13
Simply add them up vertically to give 0 +6Y=18, so Y = 3
The rest is by substitution - easy.
Or you could just add up
x-y = -1
5x+y=13
to give 6x = 12 and x = 2.
It doesn't matter - what matters is that you can x / + - any equation by a number that works to allow esy elimintion of one of the variables, as long as you do it to both sides.
5x+y=13
x-y = -1
5x+y=13
Mutiply x-y = -1 by (-5), which gives -5x+5y=5
You now have:
-5x+5y=5
5x+y=13
Simply add them up vertically to give 0 +6Y=18, so Y = 3
The rest is by substitution - easy.
Or you could just add up
x-y = -1
5x+y=13
to give 6x = 12 and x = 2.
It doesn't matter - what matters is that you can x / + - any equation by a number that works to allow esy elimintion of one of the variables, as long as you do it to both sides.
2015-10-22 1:52 am
Graph the two linear equations and the point where the two lines intersect will be the solution of the two equations in two unknowns.
參考: http://www.meta-calculator.com/online/
http://www.meta-calculator.com/online/?panel-102-graph&data-bounds-xMin=-10&data-bounds-xMax=10&data-bounds-yMin=-7.28&data-bounds-yMax=7.28&data-equations-0=%22x-y%2B1%20%3D%200%22&data-equations-1=%225*x%20%2B%20y%20%3D%2013%22&data-points-0=%5B2%2C3%5D&data-rand=undefined&data-hideGrid=false
2015-10-21 7:55 pm
X=2 y=3
2015-10-21 6:09 pm
x-y+1=0 i.e. y= x+1 ....(i)
& 5x+y=13
i.e. 5x+ (x+1)=13 [from(i)]
i.e. 6x+1=13
i.e. 6x=13-1
i.e. 6x=12
i.e. x= 12/6 =2
from (i).
y= x+1 = 2+1 = 3
& 5x+y=13
i.e. 5x+ (x+1)=13 [from(i)]
i.e. 6x+1=13
i.e. 6x=13-1
i.e. 6x=12
i.e. x= 12/6 =2
from (i).
y= x+1 = 2+1 = 3
2015-10-21 1:31 pm
x - y + 1 = 0
5x + y = 13
5x + (x + 1) = 13
6x = 12
x = 2
y = 3
5x + y = 13
5x + (x + 1) = 13
6x = 12
x = 2
y = 3
2015-10-21 1:24 pm
x - y = -1
5x + y = 13 Just add
6x = 12, x = 2, y = 3
If you prefer substitution use y = x + 1
5x + x + 1 = 13
6x = 12, x = 2, y = 3
5x + y = 13 Just add
6x = 12, x = 2, y = 3
If you prefer substitution use y = x + 1
5x + x + 1 = 13
6x = 12, x = 2, y = 3
2015-10-21 6:14 am
x-y = -1 -------------------- equation 1
5x+y=13 ------------------- equation 2
step 1: multiply equation 1 by 5 and we get 5x-5y+5=0 ----------- new equation 1
step 2: subtract new equation 1 by equation 2
we get -6y=18 => y=3
step 3: Sub y back to equation 1
x-3=-1 => x=2
5x+y=13 ------------------- equation 2
step 1: multiply equation 1 by 5 and we get 5x-5y+5=0 ----------- new equation 1
step 2: subtract new equation 1 by equation 2
we get -6y=18 => y=3
step 3: Sub y back to equation 1
x-3=-1 => x=2
2015-10-21 2:59 am
x - y = -1
5x + y = 13 Just add
6x = 12, x = 2, y = 3
If you prefer substitution use y = x + 1
5x + x + 1 = 13
6x = 12, x = 2, y = 3
5x + y = 13 Just add
6x = 12, x = 2, y = 3
If you prefer substitution use y = x + 1
5x + x + 1 = 13
6x = 12, x = 2, y = 3
2015-10-20 11:17 pm
x - y = - 1
5x + y = 13_______ADD
6x = 12
x = 2
y = 3
5x + y = 13_______ADD
6x = 12
x = 2
y = 3
2015-10-22 12:55 am
x=2, y=3
2015-10-21 3:39 pm
Mathway.com
2015-10-21 12:43 am
Khanacademy.com
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