The given expression is (2a+b)2−4(2a+b)+3
Taking 2a + b = x, the expression reduces to
x2−4x+3
The product of first and last term is 3x2
The middle term is -4x
So, two terms whose product is 3x2 and sum is −4x will be
−3x and−x
So, splitting the middle term we get,
= x2−x−3x+3
= x(x−1)−3(x−1)
= (x−3)(x−1) [Taking (x-1) common]
Substituting back the value of x we get
(2a+b−3)(2a+b−1)