下列计算错误的是 ( )
( - 3 a b 2 ) 2 = 9 a 2 b 4
- 6 a 3 b ÷ 3 ab = - 2 a 2
( a 2 ) 3 - ( - a 3 ) 2 = 0
( x + 1 ) 2 = x 2 + 1
下列运算正确的是 ( )
A. ( a 2 ) 5 = a 7 B. 3 a 3 b 2 ÷ a 2 b 2 = 3 ab
C. 4 b 3 + 2 b 3 + b 3 = 6 b 3 D. ( a − b ) ( − a − b ) = b 2 − a 2
下列计算正确的是 ( )
2 a + 3 b = 5 ab
( 3 ab ) 2 = 9 a b 2
2 a · 3 b = 6 ab
2 a b 2 ÷ b = 2 b
下列运算中,正确的是 ( )
A. 5 - 2 5 = - 2 B. 6 a 4 b ÷ 2 a 3 b = 3 ab
C. ( - 2 a 2 b ) 3 = - 8 a 6 b 3 D. a a - 1 · a 2 - 2 a + 1 1 - a = a
2 x 2 + x 2 = 2 x 4
x 3 · x 3 = 2 x 3
( x 5 ) 2 = x 7
2 x 7 ÷ x 5 = 2 x 2
A. ( 2 a 2 ) 2 = 2 a 4 B. 6 a 8 ÷ 3 a 2 = 2 a 4 C. 2 a 2 · a = 2 a 3 D. 3 a 2 − 2 a 2 = 1
A. 2 x + 3 y = 5 xy B. ( - 2 x 2 ) 3 = - 6 x 6
C. 3 y 2 · ( - y ) = - 3 y 2 D. 6 y 2 ÷ 2 y = 3 y
下列等式成立的是 ( )
2 + 2 = 2 2
( a 2 b 3 ) 2 = a 4 b 6
( 2 a 2 + a ) ÷ a = 2 a
5 x 2 y - 2 x 2 y = 3
A. 3 a 2 - 6 a 2 = - 3 B. ( - 2 a ) · ( - a ) = 2 a 2
C. 10 a 10 ÷ 2 a 2 = 5 a 5 D. - ( a 3 ) 2 = a 6
3 y + 5 y = 8 y 2
3 y - 5 y = - 2
3 y × 5 y = 15 y 2
3 y ÷ 5 y = 3 5 y
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
m 2 · m 4 = m 8
( - 2 mn ) 2 = 4 m 2 n 2
( m 2 ) 3 = m 5
3 m 3 n 2 ÷ m 2 n 2 = 3 mn
A. 3 a + 2 a = 5 a 2 B. - 8 a 2 ÷ 4 a = 2 a C. ( - 2 a 2 ) 3 = - 8 a 6 D. 4 a 3 · 3 a 2 = 12 a 6
A. 7 ab - 5 a = 2 b B. ( a + 1 a ) 2 = a 2 + 1 a 2
C. ( - 3 a 2 b ) 2 = 6 a 4 b 2 D. 3 a 2 b ÷ b = 3 a 2
下列运算结果正确的是 ( )
A. 3 a − a = 2 B. ( a − b ) 2 = a 2 − b 2
C. 6 a b 2 ÷ ( − 2 ab ) = − 3 b D. a ( a + b ) = a 2 + b