Question

factorise 3x³-48x and x4-625

Answer 1

Heya ✋

$(a)3x ^{3} - 48x \\ \\ = 3x(x ^{2} - 16) \\ \\ = 3x(x ^{2} - 4 ^{2}) \\ \\ = 3x(x + 4)(x - 4)$


$(b)x ^{4} - 625 \\ \\ = (x ^{2}) ^{2} - (25) ^{2} \\ \\ = (x ^{2} + 25)(x ^{2} - 25) \\ \\ = (x ^{2} + 25)(x ^{2} - 5 ^{2}) \\ \\ = (x ^{2} + 25)(x + 5)(x - 5)$







Thanks :)))))

Answer 2

1- 3x(x^2-16)=3x(x^2-4^2)=3x(x+4)(x-4)
2- (x^2-25)(x^2+25)=(x-5)(x+5)(x^2+25)
{note: both the above questions are factorised using the identity a^2-b^2=(a+b)(a-b)}
thank u,hope it helps!