用平方差公式(x+5)²-(x-3)²的值

问题描述:

用平方差公式(x+5)²-(x-3)²的值

=[(x+5)+(x-3)][(x+5)-(x-3)]
=(x+5+x-3)(x+5-x+3)
=8(2x+2)
=16x+16