Find angle measure for this circle!!

Please include an explanation

3. solve by graphing: y = 2x + 6 x + y = -3

The classrooms are trying to raise $1,200.00 for charity. mrs. leblanc's class has raised 50%. mr. patel's class has raised $235.14 ms. warner's class has raised 1/3 as much as mrs. leblanc's class. how much more money is needed to reach the goal of $1,200.00?

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?