Question

a-b=-8 and ab=-12, then a^3 -b^3=

Answer 1

Answer:

(a - b) = -8

(a - b)² = (-8)²

a² + b² - 2ab = 64

we know that, ab = -12

therefore,

a² + b² -2×(-12) = 64

a² + b² + 24 = 64

a² + b² = 40

now, factoring the

(a³ - b³) from we get the following factors,

(a³ - b³) = (a - b)(a² + b² + ab)

(a³ - b³) = (-8) {(40) + (-12)}

(a³ - b³) = -8 × 28

a³ - b³ = -224