已知X2-5X=3,求(X-1)(2x-1)-x(x+3)+15/x2-3的值已知x²-5x=3,求(x-1)(2x-1)-x(x+3)+15/x²-3的值.

已知X2-5X=3,求(X-1)(2x-1)-x(x+3)+15/x2-3的值已知x²-5x=3,求(x-1)(2x-1)-x(x+3)+15/x²-3的值.
已知X2-5X=3,求(X-1)(2x-1)-x(x+3)+15/x2-3的值
已知x²-5x=3,求(x-1)(2x-1)-x(x+3)+15/x²-3的值.

已知X2-5X=3,求(X-1)(2x-1)-x(x+3)+15/x2-3的值已知x²-5x=3,求(x-1)(2x-1)-x(x+3)+15/x²-3的值.
答：
x²-5x=3
(x-1)(2x-1)-x(x+3)+15/(x²-3)
=2x²-3x+1-x²-3x+15/(5x)
=x²-5x-x+1+3/x
=3-x+1+3/x
=4-x+3/x
=4+(3-x²)/x
=4+(-5x)/x
=4-5
=-1

自己想去 ................................