<PRE><B>Question 37197</B>
From 5x = 4y - 7 and 4x = 5y - 2, we will have to multiply the first equation by 4 and the second equation by 5, which gives us
20x = 16y - 28
20x = 25y - 10
The idea is to subtract these equations so that one variable is eliminated.  When we subtract them, we get
0 = -9y - 18  and
y = -2
Plugging that value in above, you get
5x = 4(-2) - 7
5x = -15
x = -3</PRE>