hi
H =( 3x+5)² - (x-8)²
H= ( 3x+5 + (x-8) ) ( 3x+5 - (x-8) )
H = ( 3x+5 +x -8) ( 2x +13)
H = ( 4x -3) ( 2x+13)
I = (x - 3)² - 16 + (x + 1)(x + 2)
I = (x-3 +4 ) ( x-3 -4) + ( x+1) ( x+2)
I = ( x+1) ( x-7) + (x+1) (x+2)
I = (x+1) ( x-7 + x+2)
I = (x+1) ( 2x-5)