A．-1
B．0
C．1
D．5
[主观题]已知x={1:1,2:2}，那么执行语句x[2]=4之后，len(x)的值为____________。
用公式法解下列方程．（1）x2+x-12=0（2）x2-sqrt(2)x-(1)/(4)=0（3）x2+4x+8=2x+11（4）x（x-4）=2-8x（5）x
求下列函数的导数： (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1
求下列函数的导数： (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1
求下列函数的导数： (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1
求下列函数的导数： (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1
求下列函数的导数： (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1) =((2x+5))^4; (1
解下列方程：(1)x2+x=0；(2)x2-2√3x=0；(3)3x2-6x=-3；(4)4x2-121=0；(5)3x(2x+1)=4x+2；(6)(x-4)
) (x)_(1)+4(x)_(2)-2(x)_(3)+8(x)_(4)=2 -(x)_(1)+2(x)_(2)+3(x)_(3)+4(x)_(4)=1 (x)
求下列不等式的解集：(1)13-4x^2>0；(2)(x-3)(x-7)<0；(3)x^2-3x-10>0；(4)-3x^2+5x-4>0求下列不等式的解集：(