Hi Walter,

You have the equation $(4w-28)+(11w+13)=180$ and you want to find a sequence of equivalent equations that ends with $w = \mbox{ something.}

First of all you can remove the parentheses on the left side of the equation so that it becomes

\[4w-28+11w+13=180.\]

Gathering the terms containing $w$ gives $4w+11w=15w.$ Also on the left you have $-28+13=-15$ so the equation becomes

\[15w-15=180.\]

You only want terms involving $w$ on the left side so add 15 to each side to obtain

\[15w-15+15=180+15\]

and hence

\[15w=195.\]

Finally multiply each side by $\frac{1}{15}$ to get

\[\frac{1}{15}\times 15w=\frac{1}{15}\times195\]

or

\[w = 13.\]

Penny