SOLUTION: I am supposed to solve using the substitution method. 5x-6y=-20 5x+45=y Here is what I have tried and I think it is wrong. I switched the 2nd equation so that it read y=5x+45.

Algebra ->  Expressions-with-variables -> SOLUTION: I am supposed to solve using the substitution method. 5x-6y=-20 5x+45=y Here is what I have tried and I think it is wrong. I switched the 2nd equation so that it read y=5x+45.      Log On


   

Question 428063: I am supposed to solve using the substitution method.
5x-6y=-20
5x+45=y
Here is what I have tried and I think it is wrong.
I switched the 2nd equation so that it read y=5x+45.
It was then,
5x-6y=-20
y=5x+45
Here is how I worked it out
5x-6(5x+45)=-20
5x-30x-270=-20
-35x-270+270=-20+270
-35x=250 and I divided both sides by -35 and got 7.14 but I know this is wrong and I do not know where or what I did wrong.
Found 3 solutions by Alan3354, mananth, nerdybill:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
I am supposed to solve using the substitution method.
5x-6y=-20
5x+45=y
Here is what I have tried and I think it is wrong.
I switched the 2nd equation so that it read y=5x+45.
It was then,
5x-6y=-20
y=5x+45
Here is how I worked it out
5x-6(5x+45)=-20
5x-30x-270=-20
-35x-270+270=-20+270 ************** Should be -25x
then x = -10
y = -5

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
5x-6y=-20
5x+45=y
5x-6y=-20 .............1
y=45+5x ---------2
plug the value of y in (1)
5x-6(45+ 5x)=-20
5x-270-30x=-20
5x-30x=-20+270
-25x=250
/-25
x=-10
Plug the value of x in (1)
5x-6y=-20
5*-10-6y =-20
-50-6y=-20
-6y=30
/-6
y=-5

CHECK
y=45+5x
-5=45-50

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
I am supposed to solve using the substitution method.
5x-6y=-20
5x+45=y
Here is what I have tried and I think it is wrong.
I switched the 2nd equation so that it read y=5x+45.
It was then,
5x-6y=-20
y=5x+45
Here is how I worked it out
5x-6(5x+45)=-20
5x-30x-270=-20 (SO FAR, SO GOOD!)
-35x-270+270=-20+270 (HERE, YOU SIMPLY COMBINED THE X TERMS INCORRECTLY)
.
SHOULD BE:
-25x-270+270=-20+270
-25x=250
x = -10
.
substitute above into:
5x+45=y
5(-10)+45=y
-50+45=y
-5 = y