Question 240544
Hello, 
Let's take the second equation and get y alone. To do that we add 7x to both sides. That will give us: 
y=7x+29  Now we can put this into the first equation:
7x+3(7x+29)=-25  Distribute and combine like terms we get:
28x + 87=-25    Now subtract 87 from both sides gives us: 
28x = -112   Divide both sides by 28 gives us: 
x = -4    To find y just plug -4 into either equation and we get:
y=1  To see if these are right plug both values into both equations and it should come out the same. 
RJ Toftness
www.math-unlock.com