Why would "-7" in the expression (x^2+-7) become positive?

(this is a genuine question not a test one)

x is the variable that's representing a number so -7 would not become posting

Please help me with with this science question

How does potassium dihydrogen phosphate affect soil, water, and air?

one that is bigger than 3 1/2

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