How do you write $f(x)=-3x^2+18x-26$ in vertex form?

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Answer 1 · 2017-04-02T11:51:00

$y=-3(x-3)^2+1$

For a detailed method (different numbers) see https://socratic.org/s/aDvvq6uD

Set $y=-3(x^2+18/(-3)x)-26$

$y=-3(x+18/(-3xx2))^2+k-26$

but $k+(-3)(18/(-3xx2))^2 = 0 => k-27=0=>k=+27$

giving:

$y=-3(x+18/(-3xx2))^2+1$

$y=-3(x-3)^2+1$

Tony B

How do you write f(x)=-3x^2+18x-26f(x)=-3x^2+18x-26 in vertex form?