Range are the y-values. Plug the x-values into the equation and solve for y.
f(x) = 3x - 2
f(-1) = 3(-1) - 2
= -3 - 2
= -5
f(0) = 3(0) - 2
= 0 - 2
= -2
R: -5 ≤ y < -2 ⇒ [-5, -2)
********************************
f(x) = 2x + 3
f(0) = 2(0) + 3
= 0 + 3
= 3
f(5) = 2(5) + 3
= 10 + 3
= 13
R: 3 ≤ y < 13 ⇒ [3, 13)
Now, put them together: [-5, -2) U [3, 13)
Answer: A