Question

Using suitable identity, find the value of $(61{)}^3$

Answer 1

$(61{)}^3=(60+1{)}^3$

Apply: $(a+b{)}^3=a^3+b^3+3ab(a+b)$

$(60+1{)}^3=(60{)}^3+(1{)}^3+3\times 60\times 1(60+1)$

$=216000+1+180\left(61\right)$

$=216001+10980$

$=226981$