Answer:
y ≥ 6.25
Step-by-step explanation:
f(x)=4x²+2x-6
positive (4) leading coefficient, curve is left up and right up
x coordinate of vertex: x = - b/2a = - 2/2*4 = - 1/4 (-0.25)
y = 4*(-1/4)² + 2*(-1/4) - 6 = -6 1/4 (-6.25) ... extreme
range: y ≥ - 6.25 [-6.25,∞)