Question

A+3(a−1)=3(2+1) this is hard and my brain hurts pls help

Answer 1

∴ a = -4.61 or 2.61 (to 3sf)

Explanation:

(a + 3)(a - 1) = 3(2 + 1)

a² + 3a - a - 3 = 3(3)

a² + 2a - 3 = 9

a² + 2a - 3 - 9 = 0

a² + 2a - 12 = 0

[(a + 1)² - 1²] - 12 = 0

(a + 1)² - 13 = 0

(a + 1)² = 13

∴ a = -4.61 or 2.61 (to 3sf)