> 数学 >
已知x方-2x=2,求(x+1)的平方+(x+3)(x-3)+(x-3)(x+1)的值.
人气:259 ℃ 时间:2020-09-21 11:46:18
解答
x^2-2x=2,
x^2-2x+1=3,
(x-1)^2=3,
x-1=±√3,x=1±√3.
(x+1)^2+(x+3)(x-3)+(x-3)(x+1)
=[(x+1)^2+(x-3)(x+1)]+(x+3)(x-3)
=2(x+1)(x-1)+(x+3)(x-3)
=2(x^2-1)+(x^2-9)
=3*x^2-11
=3*[(1±√3)^2]-11
=3*(4±2√3)-11
=1±6√3
推荐
猜你喜欢
© 2024 79432.Com All Rights Reserved.
电脑版|手机版