Question

simplify (4a-3)^3 - (4a+3)^3

Answer 1

Answer:

288a²-54 will be answer.

Answer 2

Answer:

Let us expand the given expression:

(4a – 3)3 – (4a + 3)3 = [(4a)3 – {3 ×(4a)2 × 3 } + {3 ×(4a)×(3)2 } – (3)3 ] – [(4a)3 +{3 × (4a)2 × 3} + {3 ×(4a)×(3)2} + (3)3]

By using the formula,

(a + b)3 = a3 + 3a2b + 3ab2 + b3 and (a – b)3 = a3 – 3a2b + 3ab2 – b3

= [64a3 – {3 × 16a2 × 3} + {3 × 4a × 9} – 27] – [64a3 + {3 × 16a2 × 3} + {3 × 4a × 9} + 27]

= [64a3 – 144a2 + 108a – 27] – [64a3 + 144a2 + 108a + 27]

= 64a3 – 144a2 + 108a – 27 – 64a3 – 144a2 – 108a – 27

= – 288a2 – 54

∴ (4a – 3)3 – (4a + 3)3 = -288a2 – 54