How do you write the function in standard form y=-(9x+2)^2+4x?

1 Answer
Nov 11, 2017

To put equations in standard form we must reorganize them from highest to lowest power.

Explanation:

(9x+2)(9x+2) = 81x^2 + 36 + 4

y = - (81x^2+36x+4) + 4x

distribute the negative to the parentheses

y = -81x^2 color(red)(-36x) -4 + color(red)(4x)

y = -81x^2 -32x -4

as you can see this a quadtratic function so our y = 0 because a quadratic equation gives us the x values.

0=-81x^2 -32x -4

add everything to the 0 making terms positive (which is required for standard form)

81x^2 + 32x +4 = 0

as you can see it is now it is in order of highest powers to lowest and in standard form