Question

Which of the following is the minimum value of the equation y = 2x2 + 5?

Answer 1

(0, 5) is the minimum value.

Find the axis of symmetry by plugging the respective variables into -b/2a

-5/2(0) = 0

There is no b-value in our equation, or rather, the value of b is 0. To see this, y = 2x^2 + 5 can be written as

y = 2x^2 + 0x + 5

We plug 0 into f(x), establishing every x-value as 0.

f(0) = 2(0)^2 + 5
f(0) = 0 + 5
f(0) = 5

5 is now your vertex’s y-value. Plot the two values together.

(0, 5)

We know that this is a minimum because the leading coefficient is positive, meaning the the graph’s parabola will open down.