省略乘号写出下面各式.2.8×x= y×4×y= a×4= 7×x+4= x×y= 1×h×4= x×x= (a+b)×5=
①2.8×x=2.8x;
②y×4×y=4y2;
③a×4=4a;
④7×x+4=7x+4;
⑤x×y=xy;
⑥1×h×4=4h;
⑦x×x=x2;
⑧(a+b)×5=5(a+b).
故答案为:2.8x;4y2;4a;7x+4;xy;4h;x2;5(a+b).
②y×4×y=4y2;
③a×4=4a;
④7×x+4=7x+4;
⑤x×y=xy;
⑥1×h×4=4h;
⑦x×x=x2;
⑧(a+b)×5=5(a+b).
故答案为:2.8x;4y2;4a;7x+4;xy;4h;x2;5(a+b).
温馨提示:答案为网友推荐,仅供参考