substitute 3x - y = 7 2x - 2y = 2?
回答 (8)
2016-07-11 9:12 am
3x - y = 7 ...... [1]
2x - 2y = 2 ...... [2]
[2] /2 :
x - y = 1
x = y + 1 ...... [3]
Substitute [3] into [1] :
3(y + 1) - y = 7
3y + 3 - y = 7
2y = 4
y = 2
Substitute y = 2 into [3]
x = 2 + 1
x = 3
Hence, x = 3 and y = 2
2x - 2y = 2 ...... [2]
[2] /2 :
x - y = 1
x = y + 1 ...... [3]
Substitute [3] into [1] :
3(y + 1) - y = 7
3y + 3 - y = 7
2y = 4
y = 2
Substitute y = 2 into [3]
x = 2 + 1
x = 3
Hence, x = 3 and y = 2
2016-07-11 9:13 am
Well,
3x - y = 7 ==> y = 3x - 7
that we replace in the second equation
2x - 2(3x - 7) = 2
x - (3x - 7) = 1 <-- divide by 2
x - 3x + 7 = 1
-2x + 7 = 1
2x = 7 - 1
2x = 6
x = 3
x=3 and y = 3x - 7 ==> y = 9 - 7 = 2
conclusion :
x=3
y=2
hope it' ll help !!
3x - y = 7 ==> y = 3x - 7
that we replace in the second equation
2x - 2(3x - 7) = 2
x - (3x - 7) = 1 <-- divide by 2
x - 3x + 7 = 1
-2x + 7 = 1
2x = 7 - 1
2x = 6
x = 3
x=3 and y = 3x - 7 ==> y = 9 - 7 = 2
conclusion :
x=3
y=2
hope it' ll help !!
2016-07-14 6:08 pm
From 3x - y = 7, y=3x-7. It substituted to second equation,
2x-2*(3x-7)=2
2x-6x+14=2
14-4x=2
-4x=-12
x=(-12)/(-4)=3.
Thus 3*3-y=7, y=9-7=2
2x-2*(3x-7)=2
2x-6x+14=2
14-4x=2
-4x=-12
x=(-12)/(-4)=3.
Thus 3*3-y=7, y=9-7=2
2016-07-11 10:33 am
2 X - 2 Y = 2 (1)
3 X - Y = 7 (2)
Consider equation (1)
2 ( X - Y ) = 2
X - Y = 1
X = 1 + Y Sub this into equation (2)
3 ( 1 + Y ) - Y = 7
3 + 3 Y - Y = 7
2 Y = 4
.
Y = 4 / 2
Y = 2
X = 1 + Y
X = 1 + 2
X = 3
Therefore, X = 3 and Y = 2
3 X - Y = 7 (2)
Consider equation (1)
2 ( X - Y ) = 2
X - Y = 1
X = 1 + Y Sub this into equation (2)
3 ( 1 + Y ) - Y = 7
3 + 3 Y - Y = 7
2 Y = 4
.
Y = 4 / 2
Y = 2
X = 1 + Y
X = 1 + 2
X = 3
Therefore, X = 3 and Y = 2
2016-07-11 9:58 am
2x - 2y = 2
2(x - y) = 2
x - y = 1
x = 1 + y
3x - y = 7
3(1 + y) - y = 7
3 + 3y - y = 7
2y = 4
y = 2
x = 3
2(x - y) = 2
x - y = 1
x = 1 + y
3x - y = 7
3(1 + y) - y = 7
3 + 3y - y = 7
2y = 4
y = 2
x = 3
2016-07-11 9:25 am
y = 3x - 7
2x - 2 [ 3x - 7 ]= 2
- 4x + 14 = 2
12 = 4x
x = 3
9 - y = 7
y = 2
x = 3 , y = 2
2x - 2 [ 3x - 7 ]= 2
- 4x + 14 = 2
12 = 4x
x = 3
9 - y = 7
y = 2
x = 3 , y = 2
2016-07-11 9:22 am
Multiply 3x-y =7 to get 6x - 2y = 14
subtract 6x - 2y = 14 and 2x - 2y = 2
So,
6x - 2y = 14
-
2x - 2y = 2
___________
4x - 0 = 12
so 4x = 12
rearrange for x to get x = 12/4 which is 3.
substitute x = 3 into the first equation so 3(3) - y = 7 .... 9 - y = 7 . ... y= 2
subtitute both x= 3 and y =2 into the second equation and the result should be 2.
subtract 6x - 2y = 14 and 2x - 2y = 2
So,
6x - 2y = 14
-
2x - 2y = 2
___________
4x - 0 = 12
so 4x = 12
rearrange for x to get x = 12/4 which is 3.
substitute x = 3 into the first equation so 3(3) - y = 7 .... 9 - y = 7 . ... y= 2
subtitute both x= 3 and y =2 into the second equation and the result should be 2.
2016-07-11 9:14 am
3x - y = 7
2x - 2y = 2
2x - 2(3x - 7) = 2
4x = 12
x = 3
y = 2
2x - 2y = 2
2x - 2(3x - 7) = 2
4x = 12
x = 3
y = 2
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