180-X 1/4X=180-X 1/5(180-X)怎样解
问题描述:
180-X 1/4X=180-X 1/5(180-X)怎样解
答
180-X+1/4X=180-X+1/5(180-X)
1/4X=36-1/5X
1/4X+1/5X=36
9/20X=36
X=36÷9/20
X=80