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下列运算正确的是 ( )
A. ( - 2 a ) 2 = - 4 a 2 B. ( a + b ) 2 = a 2 + b 2
C. ( a 5 ) 2 = a 7 D. ( - a + 2 ) ( - a - 2 ) = a 2 - 4
4张长为 a 、宽为 b ( a > b ) 的长方形纸片,按如图的方式拼成一个边长为 ( a + b ) 的正方形,图中空白部分的面积为 S 1 ,阴影部分的面积为 S 2 .若 S 1 = 2 S 2 ,则 a 、 b 满足 ( )
2 a = 5 b
2 a = 3 b
a = 3 b
a = 2 b
3 a 2 - 2 a 2 = a 2
- ( 2 a ) 2 = - 2 a 2
( a - b ) 2 = a 2 - b 2
- 2 ( a - 1 ) = - 2 a + 1
m 2 · m 3 = m 6
( m 4 ) 2 = m 6
m 3 + m 3 = 2 m 3
( m - n ) 2 = m 2 - n 2
2 x 2 y + 3 xy = 5 x 3 y 2
( - 2 a b 2 ) 3 = - 6 a 3 b 6
( 3 a + b ) 2 = 9 a 2 + b 2
( 3 a + b ) ( 3 a - b ) = 9 a 2 - b 2
下列计算正确的是 ( )
a 2 + a 3 = a 5
a 8 ÷ a 4 = a 4
( - 2 ab ) 2 = - 4 a 2 b 2
( a + b ) 2 = a 2 + b 2
5 ab - 3 a = 2 b
( - 3 a 2 b ) 2 = 6 a 4 b 2
( a - 1 ) 2 = a 2 - 1
2 a 2 b ÷ b = 2 a 2
已知实数、满足,求代数式的值.
在 的括号中添加一个关于的一次项,使方程有两个相等的实数根.
分解因式: .
已知 x + 1 x = 6 ,则 x 2 + 1 x 2 = ( )
38
36
34
32
b 3 · b 3 = 2 b 3
( a 5 ) 2 = a 10
a - ( b + c ) = a - b + c
2 a + 3 a = 5 a 2
( a + 2 b ) 2 = a 2 + 4 b 2
a 2 · a 3 = a 6
( - a b 2 ) 3 = - a 3 b 6
2 a 2 · 3 a 2 = 6 a 2
- a 2 + 2 a 2 = a 2
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