Solve these systems using substitution

7) -4x – 4y = 0
y=x - 4

9) 2x - 4y = -2
x + 2y = -5

answer is more than one

step-by-step explanation:

for this pair of functions g(x)=x-2 and f(x)=|x| is (g o f)(a)= |a| -2

step-by-step explanation:

g(x)=x-2

f(x)=|x|

(g o f)(a)=?

(g o f)(x)=g(f(x))

(g o f)(x)=g(|x|)

(g o f)(x)=|x|-2

(g o f)(a)=|a|-2

step-by-step explanation:

the answer is 128