2,X△10 =x+(x+1)+(x+2)+…+(x+9) =10x+1+2+3+……+9 =10x+9×（9+1）/2 =10x+45=75 解得x=3

分类: 作业答案 • 2021-12-28 17:11:24

问题描述：

2,X△10 =x+(x+1)+(x+2)+…+(x+9) =10x+1+2+3+……+9 =10x+9×（9+1）/2 =10x+45=75 解得x=3
是怎样算才解得x=3

答

X△10 =x+(x+1)+(x+2)+…+(x+9) =10x+1+2+3+……+9 =10x+9×（9+1）/2 =10x+45=75
10x=75-45
10x=30
x=30÷10
x=3