8.下列运算正确的是( )
| A. | a2+a3=a5 | B. | 4a+2b=6ab | C. | ${(\frac{1}{{{a^2}+1}})^0}=1$ | D. | ${(2\sqrt{5})^2}=10$ |
5.把多项式x3-xy2分解因式,下列结果正确的是( )
| A. | x(x+y)2 | B. | x(x-y)2 | C. | x(x-y)(x+y) | D. | x(x2-y2) |
20.
在一次函数y=-x+m(m为正整数)的图象上取点P,作PA⊥x轴,PB⊥y轴,垂足分别为A、B,且矩形OAPB的面积为4,若这样的P点只有2个,则满足条件的m的值有( )个.
0 282949 282957 282963 282967 282973 282975 282979 282985 282987 282993 282999 283003 283005 283009 283015 283017 283023 283027 283029 283033 283035 283039 283041 283043 283044 283045 283047 283048 283049 283051 283053 283057 283059 283063 283065 283069 283075 283077 283083 283087 283089 283093 283099 283105 283107 283113 283117 283119 283125 283129 283135 283143 366461
| A. | 2个 | B. | 3个 | C. | 4个 | D. | 5个 |