A quadratic equation is given below. 2x² - 8x + c = y If the graph of this quadratic equation has a minimum value at (2, 10), what is the value of c?
The parabola that has a minimum value at (2, 10) is: y - 10 = 2(x - 2)2
Multiplying this out: y - 10 = 2(x2 - 4x + 4)
y - 10 = 2x2 - 8x + 8
y = 2x2 - 8x + 18
So: c = 18
