Question

Expand each of the following using suitable identities:

a) (a + 3b + c)²​

PLEASE DO IT ON A ROUGH PAGE​

Answer 1

(a+3b+c)²

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

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

=a²+3ab+ac+3ab+9b²+3bc+ac+3bc+c²

=a²+6ab+2ac+9b²+6bc+c²