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The equation of the line of symmmetry of the curve y = x^2 + px + 21 is x = 4. Find the value of p.

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Comments

-9.25

kirtan bhatt - 7 years, 6 months ago

p = -8. Since, in the vertex form of the quadratic function, f(x) = a(x-h)^2 + k, x = h is the equation of the line of symmetry. In order to make x = 4 be the line of symmetry, f(x) must be (x-4)^2 + k. And this implies that the coefficient of x is -8. Hence, the answer.

John Ashley Capellan - 7 years, 6 months ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$