Question

if a+b=10 and ab=20, find the value of a^3+b^3

Answer 1

Hey mate, here is your answer :)

♧♧♧♧♧♧♧♧♧♧♧♧♧♧♧♧♧

$\: \: \: \: {(a + b)}^{3} = {a}^{3} + {b}^{3} + 3ab(a + b) \\ \: \: \: \: \: \: \: \: \: \: \: {(10)}^{3} = {a}^{3} + {b}^{3} + 3(20)(10) \\ \: \: \: \: \: \: \: \: \: \: \: \: 1000 = {a}^{3} + {b}^{3} + 600 \\ 1000 - 600 = {a}^{3} + {b}^{3} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: 400 = {a}^{3} + {b}^{3}$

$Hence, \: the \: value \: of \: {a}^{3} + {b}^{3} \: is \: 400$

♧♧♧♧♧♧♧♧♧♧♧♧♧♧♧♧

HOPE it helps to you!!!