Question

Si A3-b3=19y a-b=1 calcular ab

Answer 1

a³-b³=19...(1)
a-b=1.......(2)

de (2)
a-b=1
(a-b)²=1²
a²-2ab+b²=1
a²+b²=1+2ab.....(3)

de (1) desarrollo y reemplazo (2) y (3)
a³-b³=19
(a-b)(a²+ab+b²)=19
(a-b)(a²+b²+ab)=19
(1)(1+2ab+ab)=19
3ab=19-1
3ab=18
ab=18/3
ab=6

espero te sirva...