A: What did she do? B: She ______.
A:dance
B:dancer
C:danced
方程是等式.
①4x+8=0变形为x+2=0;
②x+6=5﹣2x变形为3x=﹣1;
③ 4x5 =3变形为4x=15;
④4x=2变形为x=2.