Question

Expand the following(3a – 4b – 3c)²​

Answer 1

Step-by-step explanation:

(a-b-c)² = a²+b²+c² - 2ab + 2bc - - 2ca

=> a = 3a , b = 4b and c = 3c

=> (3a)² + (4b)² + (3c)²-2(3a)(4b)+2(4b)(3c)-2(3c)(3a)

=> 9a² + 16b² + 9c² - 24ab + 24bc - 18ac

Answer 2

(3a-4b-3c)^2

a=3a, b=-4b, c=-3c

We have (a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ca

=(3a)^2+(-4b)^2+(-3c)^2+2(3a)(-4b)+2(-4b)(-3c)+2(-3c)(3a)

=9a^2-16b^2-9c^2-24ab-24bc-18ca