x÷(x×20分之11)=70+X÷5
x×1/(x×20分之11)=70+x×1/5
x×1/(11x/20)=70+x/5
x×20/11x=70+x/5
20/11=70+x/5
x/5=20/11-70
11x=100-3850
11x=-3750
X=-3750/11