Question

Which equation below represents a parabola that opens upward with a vertex at (0, – 5)?

Options

• y = x² + 5

• y = x² – 5

• y = (x – 5)²

• y = (x + 5)²

Answer 1

y = x² + 5

Explanation:

(a) y = x² + 5 ⇒ – 5 = (0)² + 5 ⇒ – 5 ≠ 5

∴ It is not correct.

(b) y = x² – 5 ⇒ – 5 = (0)² – 5 ⇒ – 5 = – 5

∴ It is correct.

(c) y = (x – 5)² ⇒ – 5 = (0 – 5)² ⇒ – 5 ≠ 25

∴ It is not correct.

(d) y = (x + 5)² ⇒ – 5 = (0 + 5)² ⇒ – 5 ≠ 25

∴ It is not correct.