Question

x-0.09x=728 need to see how to solve

Answer 1

0.91x =728
so x = 728/0.91 = 800 as (91x8=728)

Answer 2

\[x-0.09x = 728\]

you have on the left side two like variables so combine them
the first \[x = 1*x\]

so \[1-0.09 = 0.91\]

you then have \[0.91x = 728\]

then x = 728/0.91