Prove: if a^2-a is even then a is even.

Ahomeowner plans to hang wallpaper on one wall of a bedroom that is 10 feet long if a stripe of wallpaper is 20 inches wide and stripes or hung vertically how many stripes on wall paper with the homeowner required

How is working backward similar to solving an equation?

An 18% discount on a watch saved a shopper $72. find the price of the watch before the discount