已知x1,x2是方程2x²+4x-3=0的两根,不解方程下列各式的值.(1)x1²x2+x1x2² (2)x1²+x2²-3x1x2
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![已知x1,x2是方程2x²+4x-3=0的两根,不解方程下列各式的值.(1)x1²x2+x1x2² (2)x1²+x2²-3x1x2](/uploads/image/z/5248274-50-4.jpg?t=%E5%B7%B2%E7%9F%A5x1%2Cx2%E6%98%AF%E6%96%B9%E7%A8%8B2x%26%23178%3B%2B4x-3%3D0%E7%9A%84%E4%B8%A4%E6%A0%B9%2C%E4%B8%8D%E8%A7%A3%E6%96%B9%E7%A8%8B%E4%B8%8B%E5%88%97%E5%90%84%E5%BC%8F%E7%9A%84%E5%80%BC.%EF%BC%881%EF%BC%89x1%26%23178%3Bx2%2Bx1x2%26%23178%3B+%EF%BC%882%EF%BC%89x1%26%23178%3B%2Bx2%26%23178%3B-3x1x2)
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已知x1,x2是方程2x²+4x-3=0的两根,不解方程下列各式的值.(1)x1²x2+x1x2² (2)x1²+x2²-3x1x2
已知x1,x2是方程2x²+4x-3=0的两根,不解方程下列各式的值.
(1)x1²x2+x1x2² (2)x1²+x2²-3x1x2
已知x1,x2是方程2x²+4x-3=0的两根,不解方程下列各式的值.(1)x1²x2+x1x2² (2)x1²+x2²-3x1x2
韦达定理,X1+X2=-2,X1X2=-3/2
x1²x2+x1x2² =X1X2(X1+X2)=3
x1²+x2²-3x1x2=(X1+X2)^2-5x1x2=23/2
(1) X1X2(X1+X2) (2) (X1+X2)2-5X1X2