Question

Si a – b =4 ∧ a3 – b3 = 4, calcula: ab

Answer 1

Explicación paso a paso:

a + b = 4

ab = 7

a3+ b3=(a+b)(a2-ab+b2)

(4)(a2-7+b2)

(a+b)2=16

a2+b2+2ab=16

a2+b2+14=16

a2+b2=2

(4)(a2-7+b2)=(4)(-7+2)=4.-5=-20 RPTA