Question

QUESTION IS IN THE ATTACHMENT BOX.​

Answer 1

Answer:

$Use. binomial theorem \left(a-b\right)^{3}=a^{3}-3a^{2}b+3ab^{2}-b^{3} to expand \left(2x-1\right)^{3}. \\ (2x-1) ^ { 3 } \\ 8x^{3}-12x^{2}+6x-1$

x^{3}+12xy^{2}-8y^{3}-6yx^{2}

Answer 2

EVALUATION★

formula use all step

$\star\pink{(a-b)^3=a^3-b^3-3a^2b+3ab^2}$

(a)

$= (2x - 1) {}^{3} \\ \\ = (2x) {}^{3} - 1 {}^{3} - 3(2x) {}^{2}(1) + 3(2x)(1) {}^{2} \\ \\ = 8x {}^{3} - 1 - 12x {}^{2} + 6x$

(b)

• $= (x - 2y) {}^{3} \\ \\ = x {}^{3} - (2y) {}^{3} - 3(x) {}^{2}(2y) + 3x(2y) {}^{2} \\ \\ = x {}^{3} - 8y {}^{3} - 6x {}^{2} y + 12xy {}^{2}$

(c)

$= (5 - b) {}^{3} \\ \\ = 5 {}^{3} - b {}^{3} - 3(5) {}^{2}b + 3(5)(b) {}^{2} \\ \\ = 125 - b {}^{3} - 75b + 15b {}^{2}$

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• I hope it helps you ✅