x=2*[1.25*(x-10)-10]
问题描述:
x=2*[1.25*(x-10)-10]
答
x=2*[1.25*(x-10)-10]
x=2.5(x-10)-20
x=2.5x-25-20
2.5x-x=25+20
1.5x=45
x=30