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 (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