\(\left(3x+4\right)^2-10x-\left(x-4\right)\left(x+4\right)\)
\(=9x^2+24x+16-10x-x^2+16\)
\(=8x^2+14x\)
P = ( 3x + 4 )2 - 10x - ( x - 4 )( x + 4 )
P = 9x2 + 24x + 16 - 10x - ( x2 - 16 )
P = 9x2 + 24x + 16 - 10x - x2 + 16
P = 8x2 + 14x + 32
P = 2( 4x2 + 7x + 16 )