判断下列计算是否正确,并简要说明理由: ①a.a2=a2(×) ②a+a2=a3(×) ③a3.a3=a9(×) ④a3+a3=a6(×)
• ① a · a2＝ a2 ② a＋a2 ＝ a3 ③ a3 · a3＝ a9 ④ a3＋a3 ＝ a6 (×) (×) (×) 判断下列计算是否正确，并简要说明理由： (×)
判断(正确的打“√,错误的打“×”) (1)x4x6=x24(×) (2)xx3=x3(×) (3)x4+x4=x8( 4)x2xz2=2x4(×) (5)a2a3-a3a2=0(y) (6)x3y5=(xy)(×) (7)x7+x7=x14()
(1)x4·x6=x24 ( ) (2) x·x3=x3 ( ) (3) x4+x4=x8 ( ) (4)x2·x2=2x4 ( ) (5)a2·a3 - a3·a2 = 0 ( ) (6)x3·y5=(xy)8 ( ) (7) x7+x7=x14 ( ) √ × × × × × × 判断（正确的打“√”，错误的打“×”）