先化简,在求值:(1)已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值(2)已知x(x-1)-(x^2-y)=-3,求x^2+y^2-2xy的值

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先化简,在求值:(1)已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值(2)已知x(x-1)-(x^2-y)=-3,求x^2+y^2-2xy的值

先化简,在求值:(1)已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值(2)已知x(x-1)-(x^2-y)=-3,求x^2+y^2-2xy的值
先化简,在求值:(1)已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值
(2)已知x(x-1)-(x^2-y)=-3,求x^2+y^2-2xy的值

先化简,在求值:(1)已知x^2-5x=14,求(x-1)(2x-1)-(x+1)^2+1的值(2)已知x(x-1)-(x^2-y)=-3,求x^2+y^2-2xy的值
1、(x-1)(2x-1)-(x+1)^2+1
=2x²-x-2x+1-x²-2x-1+1
=x²-5x+1
因为x^2-5x=14
(x-1)(2x-1)-(x+1)^2+1
=14+1
=15
2、x(x-1)-(x^2-y)
=x²-x-x²+y
=y-x
=-3
x^2+y^2-2xy
=(y-x)²
=(-3)²
=9

将(x-1)(2x-1)-(x+1)^2+1化简得x^2-5x+1,将x^2-5x=14代人得15.
(2)将x(x-1)-(x^2-y)=-3化简得y-x=-3,x^2+y^2-2xy化简为(x-y)^2,则将y-x=-3代人得9

(x-1)(2x-1)-(x+1)^2+1
=2x²-3x+1-x²-2x-1+1
=x²-5x+1
=14+1
=15
x(x-1)-(x^2-y)=-3,则x²-x-x²+y=-3,则-x+y=-3,则x-y=3
则x^2+y^2-2xy=(x-y)²=3²=9

(1)(X-1)(2x-1)-(x+1)^2+1
=2x^2-3x+1-x^2-2x-1+1
=x^2-5x+1
将x^2-5x=14代入
原式=14+1=15
(2)x(X-1)-(x^2-y)=-3
x^2-x-x^2y=-3
x-y=3
x^2+y^2-2xy=(X-y)^2=3^2=9