This is pretty simple. When it asks to combine terms, simply add up all of the same terms. So, all the numbers with x, all with y, and all with no value. For example, for x, we simply add up 5x+8x+x, with x equaling 1.
Put it in an equation; it is given that 36 is the price after the 40% discount, so; 36=X*40% X here is the original price 36=X*(40/100) 40X=3600 X=90$ Hope this helps.
