Question

If a-b = -7 and ab = 2, find a³- b³
Can someone please answer this?

Answer 1

${a}^{3} - {b}^{3} = {(a - b)}^{3} + 3(ab) \times (a - b)$
so (a^3-b^3) = (-7)^3 + (3*2)*(-7)
ans is -285