What is the formula for finding the area of a trapezoid?

My math teacher told my class to "steal" a 6th grade fraction word problem from the internet, word problems? : -p requirements: only a 1 step word problem. needs to be complex.

At your job you're paid $50 per week plus $3 per sale at least how many saled do you need to make in order to have over $250

What should be done to both sides of the equation in order to solve -5m = -40? a) multiply by -5. b) divide by -5. c) multiply by -40. d) divide by -40.