How 12x square +7xy−12y square equal to (3x+4y)×(4x−3)?
Lets write the first given expression mathematically,
12x square +7xy−12y square =12x2+7xy−12y2
And we need to prove 12x2+7xy−12y2=(3x+4y)(4x−3)
Lets consider the expression written on right side,
RHS
=(3x+4y)×(4x−3)
=3x×(4x)−(3x)×(3)+(4y)×(4x)+(4y)×(−3)
=12x2−9x+16xy−12y=LHS
Hence, 12x square +7xy−12y square equal to (3x+4y)×(4x−3).