(3x-7)x2=28
3x2-[7x-(4x-3)-2x2]
(x2+3x+12)(x2+7x+12)-120
解方程7/(x+x2)-3/(x-x2)=6/(x2-1)
(1)x2+12x=0; (2)4x2-1=0; (3)x2=7x (4)x2-4x-21=0; (5)(x-1)(x+
已知x2 3x-2=0,求2x-4╱x2 6x 9÷(x-3)×x2-9╱2x-x2的值
若|x|=2,化简求值:3x2-[7x2-2(x2-3x)-2x].
4x4×x2×x-(﹣x)3×(﹣x)4-2x2×x5
x2+﹙1/6﹚x-1/3=0②x2-2x=3③x2-4x-2=0④-2x²-x+7=0⑤3x²-x
先化简,再求值:(3x2-4x+5)(3x2+4x-5)-x2(9x2-16),其中x=120
已知x2+3x+5=7,求3x2+9x+2的值
已知f(x-1/x)=x2+1/x2则函数f(3)等于?
化简:3x2-[7x-(4x-3)-2x2].