Question

find the value of l³+m³+n³-3lmn, when l+m+n=15 and lm+mn+nl=74​

Answer 1

Answer:

1395

Step-by-step explanation:

Given

l+m+n=15,

lm+mn+nl=74

To find:-

l³+m³+n³-3lmn

Solution:-

(l+m+n)²=(15)²

l²+m²+n²+2(lm+mn+nl)=225

l²+m²+n²+2(74)=225

l²+m²+n²=225-158

l²+m²+n²=167

l³+m³+n³-3lmn=(l+m+n){l²+m+n²-(lm+mn+nl)}

=(15)(167-74)

=15x93

=1395

Answer 2

find the value of l^3+m^3+n^3-3lmn when l+m+n=15 and lm+mn+no=74