I require help (why this stuff so hard)

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.