520×80%－X=4%X怎么算,求一步步解答…

题目

520×80%－X=4%X怎么算,求一步步解答…

答案

520 × 80% - x = 4% x
520 × 0.8 = 4% x + x
52 × 8 = 1.04 x
1.04 x = 416
两边乘以 100 得：
104 x = 41600
x = 400