计算:(3x+4)(3x-4)-(2x+3)(2x-3)

问题描述:

计算:(3x+4)(3x-4)-(2x+3)(2x-3)

(3x+4)(3x-4)-(2x+3)(2x-3)
=(9x²-16)-(4x²-9)
=9x²-16-4x²+9
=5x²-7