已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值

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已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值
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已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值
已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值
已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值

已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值
原式=(2x²-3x+1)-(x²+2x+1)+1
=2x²-3x+1-x²-2x-1+1
=x²-5x+1
=14+1
=15

原式=(2x²-3x+1)-(x²+2x+1)+1
=2x²-3x+1-x²-2x-1+1
=x²-5x+1
=14+1
=15

x^2-5x=14
x^2-5x-14=0
(x-7)(x+2)=0
x=7,x=-2
当x=7
(x-1)(2x-1)-(x+1)^2+1
=(7-1)(2*7-1)-(7+1)^2+1
=104-64+1
=41
当x=-2
(x-1)(2x-1)-(x+1)^2+1
=(-2-1)(2*(-2)-1)-(-2+1)^2+1
=15-1+1
=15

x^2-5x=14,解出x=7或x=-2,当x=7时,(x-1)(2x-1)-(x+1)^2+1=15,当x=-2时,(x-1)(2x-1)-(x+1)^2+1=15

.......

x^2-5x=14
x^2-5x-14=0
(x+2)(x-7)=0
x=-2或x=7
(x-1)(2x-1)-(x+1)^2+1
=2x^2-x-2x+1-x^2-2x-1+1
=x^2-5x+1
当x=-2时,原式=15
当x=7时,原式=15

o()^))o 唉。。这个题我们前天刚做完。。