The vertex of the parabola is at (4, -3). When the x-value is 5, the y-value is 6. What is the coefficient of the squared expression in the parabola's equation?
A.2
B.3
C.-3
D.-2

the sum of all the angles in a triangle are equal to 180

so you can add   the 3 given angles together to equal 180:

5y + 2y + 2y = 180

or since all three angles have the same letter, combine the 3 angles to equal 180:

9y = 180