2 questions??2 variables?

-x+3y= -25
3x-2y = 26

So from the first eqn x=25+3y
Sub in 2nd eqn
3*(25+3y) -2y = 26
so 75 +7y = 26
so 7y = -49
so y=-7 so x=4


For (2)
y = -1/3x + -1
y= -3x + 15

So subtracting 2nd from 1st
0 = 8/3 x -16
so 8x = 48 so x=6 so y=-3

x = 3y+25 ---(1)
3x-2y = 26 --- (2)
substitute 1 into 2
3(3y+25)-2y = 26
9y+75-2y = 26
7y = -49
y = -7
substitute y=-7 into 1
x = 3(-7)+25
= -21+25
= 4
therefore, x = 4 and y = -7

y = -1/3x + -1 --- (1)
y= -3x + 15 ---(2)
substitute 2 into 1
-3x+15 = -1/3x-1
3*(-3x+15) = 3*(-1/3x-1)
-9x+45 = -x-3
-8x = -48
x = 6
substitute x=6 into 2
y = -3(6)+15
= -18+15
= -3

1. express the first equation in terms of x

x = 3y + 25

Then sub it to the 2nd equation:

3(3y+25) - 2y = 26
9y + 75 - 2y = 26
7y = 26-75
7y = -49
y = -2

Then sub the value of y to the first equation:

-x + 3(-2) = -25
-x - 6 = -25
x = 19

2. Same here, use y instead because it's easier

y = -1/3x - 1
-1/3x - 1= -3x + 15
(1/3)x = 3x - 16
x = 9x - 48
-8x = -48
x = 6

y = -(1/3)(6) - 1
y = -2 - 1
y = -3

1) In the first equation, add x to each side and add 25 to each side, giving you
3y+25=x. Plug this x value into the second equation.
3(3y+25)-2y=26
Combine like terms.
9y+75-2y=26
7y=-49
Divide both sides by 7.
y=-7
Plug into first equation.
3(-7)+25=x
-21+25=x
x=4

2) Since both equations equal y, we can say
(-1/3)x -1=-3x+15
Turn -3x into a fraction.
(-1/3)x -1=(-9/3)x +15
Add (-9/3) to each side, and add 1 to each side.
(8/3)x=16
Divide both side by (8/3)
x=(16/1) / (8/3)
x=48/8=6
Plug x value into second equation.
y=-3

1.) Isolate the x in the first equation.

-x + 3y = -25
-x = -3y - 25
x = 3y + 25

Plug in 3y + 25 for x in the second equation.

3(3y + 25) - 2y = 26
9y + 75 - 2y = 26
7y = -49
y = -7

Now that you know that y equals -7, plug in -7 for y in either of the original equations.

3x - 2(-7) = 26
3x + 14 = 26
3x = 12
x = 4

Check your solutions by plugging both the x and y values into BOTH of the equations.

So your answer is (4,-7).


2.) I'll assume you want to use substitution again. Combination would probably be easier in this situation, though.

Plug in -1/3x - 1 in for y in y = -3x + 15.

-1/3x - 1 = -3x + 15
8/3x = 16
x = 6

Plug in 6 for x in one of the original equations.

y = -3(6) + 15
y = -18 + 15
y = -3

Check by plugging both values into both equations.

So your answer is (6,-3).


Hope this helps!

2) Set both equation equal to each other like this
-1/3x+ (-1)=-3x+15
Add both sides by 1
-1/3x+(-1)+1=-3x+15
Substitute
-1/3x=-3x+16
Add both sides by 3x
-1/3x+3x=-3x+3x+16
Substitute
8/3x=16
Multiply both sides by the reciprical of 3/8
(8/3x)(3/8)=16(3/8)
Solve for x
x= 6

Hope that helps!