How do you solve # -9x^2 + 18x + 27 = 0#?

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Answer 1 · 2016-07-17T16:43:40

#x = 3 or x = -1#

Divide through by -9 first. This will make the #x^2 # term positive, and change the equation into its simplest form.

#x^2 -2x -3 = 0#

Find factors of 3 which will subtract to make 2.
Signs will be different with more negatives.

The factors are 3 and 1, but we need -3 and +1.

#(x-3)(x+1) = 0#

One of the factors must be equal to 0.

If #x-3 = 0 " " x = 3#

If # x+1 = 0 " " x = -1#