Question

Pls Expand using identity:-
(i) (5m - 2n)^3
(ii) (a-2b+3c)^2
(iii) (x + 4y/3)^3

Answer 1

(i)(5m-2n)³

(a-b)³=a³-b³-3ab(a-b)

(5m-2n)³=(5m)³-(2n)³-3(5m)(2n)(5m-2n)

=125m³-8n³-30mn(5m-2n)

(ii)(a-2b+3c)²

(a+b+c)²=a²+b²+c²+2ab+2ac+2ac

(a-2b+3c)²=(a)²+(2b)²+(3c)²+2(a)(2b)+2(2b)(3c)+2(a)(3c)

=a²+4b²+9c²+4ab+12bc+6ac

(iii)(x+4y/3)³

(a+b)³=a³+b³+3ab(a+b)

(x+4y/3)³=(x)³+(4y/3)³+3(x)(4y/3)(x+4y/3)

=x³+64y/9+12xy/3(x+4y/3)