Question

find the value of a3+27b3 if a-2b=(-6) and ab=(-10)
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Answer 1

Answer:

Concept:

a³-b³=(a-b) (a²+b²+ab)

(a-b)²= a²+b²-2ab

Find:

We find the value of a³-27b³

Given:

We given a−3b=−6, ab =-10

Step-by-step explanation:

a−3b=−6

Squaring both sides,

(a−3b)² =−6²

a²+9b²−2(a)(3b)=36

a²+9b²−6(ab)=36

a²+9b²−6(−10)=36

a²+9b²=36−60

a²+9b²=−24

Now,

a³−(3b)³=(a−3b)[(a)²+(3b)²+(a)(3b)]

a³−27b³=−6(−24+3(−10))

=−6(−24−30)

=-6(-54)

=-324

Hence the value of a³-27b³ is -324