SOLUTION: I'm having a lot of trouble solving this equation using the substitution method please help. 4x-3y=2 5x+y=-7 Here is what I've tried. I solved for y in the 2nd equation and

Algebra ->  Equations -> SOLUTION: I'm having a lot of trouble solving this equation using the substitution method please help. 4x-3y=2 5x+y=-7 Here is what I've tried. I solved for y in the 2nd equation and      Log On


   

Question 882873: I'm having a lot of trouble solving this equation using the substitution method please help.
4x-3y=2
5x+y=-7
Here is what I've tried. I solved for y in the 2nd equation and plugged it into the 1st equation, combined like terms, simplified and now I'm stuck
y=5x-7
4x-3(5x-7)=2
4x-15x+21=2
-11x+21=2
what is my next move



Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
All of this is wrong because the first step is wrong, because of sign mistake.
y=5x-7
4x-3%285x-7%29=2
4x-15x%2B21=2
-11x%2B21=2+

Starting fresh from the second equation,
5x%2By=-7
5x-5x%2By=-7-5x
0%2By=-7-5x
highlight_green%28y=-5x-7%29, different formula for y than before. You will use this formula again later...
-
Now, use the first equation of your system and substitute for y to find x.
4x-3y=2
4x-3%28-5x-7%29=2
4x%2B15x%2B21=2
19x%2B21=2
19x=-19
highlight%28x=1%29

Use what you found for x to compute the value for y.