i require help (why this stuff so hard)

Answer:
x should be -3
Step-by-step explanation:
f(x) = 5/3x + 10
f(-3) = (5*-3)/3 + 10
f(-3) = -15/3 + 10
f(-3) = -5 + 10
f(-3) = 5
g(x) = -2x - 1
g(-3) = -2(-3) - 1
Negatives cancel out
g(-3) = 2(3) - 1
g(-3) = 6 - 1
g(-3) = 5
5 is equal to 5, so x should be -3 in this case.