Question

(2p‐ 1)³=
a
Expand

(3r-2k)³+(3r+2k)³
Solve

Answer 1

We know that (x+y)

3=x

3

+y

3

+3xy(x+y)

(2p−5)

3

Here x=2p and y=-5 we get

(2p)

3

−(5)

3

+3(2p)(−5)(2p−5)

=8p

3

−125−30p(2p−5)

=8p

3

−125−60p

2

+150p

=8p

3

−60p

2

+150p−125

STEP

1

:

1.1 Evaluate : (3r-2k)3 = 27r3-54r2k+36rk2-8k3

1.2 Evaluate : (3r+2k)3 = 27r3+54r2k+36rk2+8k3

STEP

2

:

Pulling out like terms

2.1 Pull out like factors :

54r3 + 72rk2 = 18r • (3r2 + 4k2)

Final result :

18r • (3r2 + 4k2)