find l³+m³+n³-3lmn when l+m+n=7 and l²+m²+n²=3
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Answered by
2
Answer:
(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
Answered by
1
Answer:
Bruh, use that (a+b+c)^3 formula. I forgot that
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