脑袋里面一阵阵的胀痛:初二代数8
来源:百度文库 编辑:查人人中国名人网 时间:2024/04/29 18:16:50
已知:a+b=1 ab=-1/2
求:a(a+b)(a-b)-a(a+b)
求:a(a+b)(a-b)-a(a+b)
.....将a+b=1代如,化为 a(a-b)-a
=a^2+ 1/2 -a
=a(a-1) + 1/2
= a(1-b-1)+1/2
=-ab +1/2
=0
已知:
a + b = 1
ab = -1/2
a(a + b)(a - b) - a(a + b)
= a(a + b)(a - b - a)
= -ab*(a + b)
= 1/2*1
= 1/2
a+b=1 a=1-b
a(a+b)(a-b)-a(a+b)
=a(1)(1-2b)-a
=a-a-2ab-a
=-1-a
=a-1