>(x*80)+((x*1.5)*20) = 1100

Make it look like:

80x + 1.5x * 20 = 1100

80x + 30x = 1100

110x = 1100

Now, divide both sides by 110, and you'll get:

x= 10

I usually like to shortcut this equailty with my patened algebra technique: Multiply Both Sides by Zero, but high school teachers don't seem to understand my logic :-)