Question

Solve by using Completing the Square

Answer 1

9x^2 + 3x = 2

Answer 2

so far I divided both sides by 9 so
x^2 + 1/3x = 2/9
Then divide 1/3 by 1/2 then square it so
x^2 + 1/3x + 1/36 = 2/9 + 1/36
so x^2 + 1/3x + 1/3 = 1/4

Answer 3

The last part should have 1/36, not just 1/3, but 1/36

Answer 4

oh, yea, I am sorry, you are correct

Answer 5

so now (x + 1/3)^2 = 1/4 right?

Answer 6

yup

Answer 7

so now I solve for x so sqrt both sides?

x + 1/3 = + or - 1/2
(When 1/2 is positive)
x + 1/3 = 1/2
- 1/3 - 1/3
x = 1/6
(When 1/2 is negative)
x + 1/3 = - 1/2
- 1/3 - 1/3
x = -5/6?

Answer 8

yup

Answer 9

I got that marked wrong too, I'll have to ask him about it..

Answer 10

Wait, let me check

Answer 11

It is wrong. I am so sorry for not pay attention at the first time I noticed you

Answer 12

\[x^2 +\dfrac{1}{3}x =\dfrac{2}{9}\]

Answer 13

and you add 1/36 both sides, hence the expression is \(x^2 +(1/3)x+(1/6)^2 \), not as what you did

Answer 14

Hence it is \((x+1/6)^2 = 1/4\)

Answer 15

ok? yes? no?

Answer 16

ohh, I understand. :/ Okay at least I know now