Express 9 +6x -3x^2 in the form a -b(x + c)^2

Answer 1

-3x^2+6 x = -3 (x^2 -2x)
so we really have
9 - 3(x^2-2x)
I would like to have (x^2 - 2 x + 4) [completing the square in there]
so
9 { - 3 (x^2 - 2 x + 4) + 12}
is
21 - 3 (x-2)^2

Answer 2

cool problem :)