3x²-2x=4 quadratic equation

Giuseppi's pizza had orders for $931.00 of pizzas. the prices were $21 for a large pizza, 514 for a medium pizza, and $7 for a small pizza. the number of large pizzas was two less than four times the number of medium pizzas. thenumber of small pizzas was three more than three times the number of medium pizzas. how many of each size of pizza were ordered?

In trapezoid abcd, ac is a diagonal and ∠abc≅∠acd. find ac if the lengths of the bases bc and ad are 12m and 27m respectively.

These tables represent a quadratic function with a vertex at (0, -1). what is the average rate of change for the interval from x = 9 to x = 10?