Question

Expand each of the following using suitable identities
1) (3a-7b-c)2​

Answer 1

➪ ( 3a-7b-c)

➪(x+y+z)^2 = x^2+y^2+z^2+2xy+2yz+2zx

➪x= 3a , y= -7 b , z= -c

➪(3a)^2+(-7b)^2+(-c)^2+2(3a)(-7b)+2(7b)(-c)+2(-c)(3a)

➪9a^2+49b^2+c^2-42ab+14bc-6ac✔︎✔︎✔︎✔︎