Question

F(x) = -5x^2 + 3x + 2
What is the axis of symmetry?
What's the coordinate of the vertex?

Answer 1

• axis of symmetry: x = 0.3
• vertex: (0.3, 2.45)

Explanation:

For quadratic ax²+bx+c, the axis of symmetry is x=-b/(2a). For your quadratic with a=-5, b=3, the axis of symmetry is ...

x = -(3)/(2(-5))

x = 3/10 . . . . axis of symmetry

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The coordinates of the vertex are found by evaluating the function at x=3/10.

f(3/10) = (-5(3/10) +3)(3/10) +2 = 1.5(3/10) +2 = 0.45 +2 = 2.45

The vertex is (0.3, 2.45).