how would you substitute this equation?
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If y = x and y = z, then by substitution we can say x = z.
In this case, substitution gives us
-1/2 x - 2 = -3/2 x + 2
and we can solve for x :
3/2 x - 1/2 x = 2 + 2
x = 4
then solve for y :
y = -1/2 x - 2
y = -1/2 * 4 - 2
y = -2 - 2
y = -4