Pembahasan:
Cara 1:
f(2x – 3) = 4x – 5
f(2x – 3) = 2(2x – 3) + 6 – 5
= 2(2x – 3) + 1
⇔ f(x) = 2x + 1
f(-7) = 2 × (-7) + 1
= -14 + 1 = -13
Cara 2:
f(2x – 3) = 4x – 5
2x – 3 = -7
⇔ 2x = -7 + 3
⇔ 2x = -4
⇔ x = -4 ÷ 2 = -2
f(-7) = 4 × (-2) – 5
= -8 – 5 = -13