SOLUTION: Hi. I'm checking to see if I solved this problem correctly. Solve each system by substitution, if possible {2x-y=-21 4x+5y=7 thanks H.C.

Algebra ->  Equations -> SOLUTION: Hi. I'm checking to see if I solved this problem correctly. Solve each system by substitution, if possible {2x-y=-21 4x+5y=7 thanks H.C.      Log On


   

Question 181413: Hi.
I'm checking to see if I solved this problem correctly.
Solve each system by substitution, if possible
{2x-y=-21
4x+5y=7
thanks
H.C.
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
Add in your solution next time please
2x-y+=+-21
-y+=+-21+-2x
y+=+21%2B2x
Substitute that into
4x%2B5y+=+7
4x+%2B+5%2A%2821%2B2x%29+=+7
4x+%2B+105+%2B+10x+=+7
14x+=+-98
x+=+-7
y+=+21+%2B2%28-7%29
y+=+7
Check your answer
Does 4*(-7) + 5*(7) = 7 ???