Question

Expand :(-3a - 5b -c) ^2

Answer 1

Answer:

As (x+y+z) = x²+y²+z²+2xyz

here x = (-3a) , y = (-5b) , z = (-c)

hence (-3a-5b-c)

=> (-3a)²+(-5b)²+(-c)²+2×(-3a)×(-5b)×(-c)

=> 9a²+25b²+c²-30abc