Solve 0 = 3x^2 + 5x -1 by completing the square. Express your answer as exact roots.

Question

3(x^2 + 5/3 + 25/36) = -1
(x+ 5/6)^2 = 37/36
sq root( x + 5/6)^2 = sq root (37/36)
x + 5/6 = +- sq root 37/6

x = -5/6 +- square root 37 /6 <---

(Sorry for the work being so messy! It'd be much neater if I could type the symbol for square root)

Answer 1

You are correct,
but write it as
x = (-5 ± √37)/6

I use a Mac and to get √7 I press "option v"

Answer 2

Thanks! But could you please explain why we take off one of the 6's?

I use a Windows PC and cant find the command for square roots

Answer 3

Because she used parentheses.

Answer 4

Thank you