A:9 =±3
B:﹣ 643 =﹣4
C:(−0.2)2 =﹣0.2
D:± 1649 = 47
f____ ____tb____ll
下列方程中变形正确的是( )①4x+8=0变形为x+2=0;②x+6=5-2x变形为3x=-1;③4x5=3变形为4x=15;
④4x=2变形为x=2