Question

1) ( x-5 ) ( x+7 ) - 7x ( x+3 )

2) ( x+5 ) ( x+7 ) - ( x-4 ) ( x+3 )

3) ( 2x-3 ) ( x+4 ) + ( -x+1 ) ( x-2 )

Answer 1

1) \(\left(x-5\right)\left(x+7\right)-7x\left(x+3\right)\)

\(=x^2+7x-5x-35-7x^2-21x\)

\(=-6x^2-19x-35\)

2) \(\left(x+5\right)\left(x+7\right)-\left(x-4\right)\left(x+3\right)\)

\(=x^2+5x+7x+35-\left(x^2+3x-4x-12\right)\)

\(=x^2+12x+35-x^2+x+12\)

\(=13x+47\)

3) \(\left(2x-3\right)\left(x+4\right)+\left(-x+1\right)\left(x-2\right)\)

\(=2x^2+8x-3x-12-x^2+2x+x-2\)

\(=x^2+8x-14\)