Question

3. WEDNESDAY (5/20): The minimum of the graph of a quadratic function is located at (-1,2). The point (2, 2015

also on the parabola. Which function represents this?
a) f(x) = x² + 2x + 3
b) f(x)= x² - 2x+3
c) f(x) = 2x²+4x+4
d) f(x)= 2x²- 4x+4​

Answer 1

C.) f(x) = 2x^2 + 4x + 4

Explanation:

The equation of the parabola with vertex (h,k) is y=a(−h+x)^2+k.

Thus, the equation of the parabola is y=a(x+1)^2+2.

To find a, use the fact that the parabola passes through the point (2,20): 20=9a+2.

Solving this equation, we get that a=2.

Thus, the equation of the parabola is y=2(x+1)^2+2.

TO STANDARD FORM

= 2*(x^2+2x+1)+2

=(2x^2+4x+2)+2

= 2x^2+4x+2+2

= 2x^2+4x+4