(4a²-3)(4a²+8)
=16a^4+32a²-12a²-24
=16a^4+20a²-24
（3x+1)(x+1)-(2x-1)(x-1)-3x(x-2)-2x(-3x)
=3x^2+3x+x+1-(2x^2-2x-x+1)-3x^2+6x+6x^2
=3x^2+3x+x+1-(2x^2-3x+1)-3x^2+6x+6x^2
=3x^2+3x+x+1-2x^2+3x-1-3x^2+6x+6x^2
=3x^2+6x^2-3x^2-2x^2+6x+3x+x+3x+1-1
=4x^2+13x