Question

Find the range of the function.
ƒ(x) = 2x^2 + 7

Answer 1

1) The minimum value of f(x) is going to be when x=0,
f(0)=7, all others positive and negative values give f(x) >7.
2) Coefficient near x² is positive, so parabola is "up".
So range is f(x)≥7, or (7,+∞).