Question

10.Prove that (a +b +c)3- a3-b3-c3= 3 (a+b) (b+c) (c +a)
11. Give the possible expressions for the length and breadth of the
Rectangle whose area is given by 4a2 +4a -3

Answer 1

2. area = l*b

4a^2 +4a -3

l*b = (4a^2 + 6a)+(-2a-3)

l*b = 2a( 2a +3) -1(2a+3)

l*b = (2a+3)(2a-1)

so l = (2a+3) or (2a-1)

b = (2a-1) or (2a+3)