数学题化简2(x-3)(x+3)-(x+3)(3-x)其中x=1
问题描述：
数学题化简2(x-3)(x+3)-(x+3)(3-x)其中x=1
2(x-3)(x+3)-(x+3)(3-x) 其中x=1
答
x=1
∴2(x-3)(x+3)-(x+3)(3-x)
=2(x²-9)+(x+3)(x-3)
=2x²-18+x²-9
=3x²-27
=3×1²-27
=3-27
=-24