# Thread: Finding the equation of a straight line.

1. ## Finding the equation of a straight line.

$
y - 4 = \frac{2}{3}(x - 2)
$

My working:

$
y - 4 = \frac{2}{3}x - \frac{4}{3}

$

Then adding four to both sides:

$
y = \frac{2}{3}x - \frac{8}{3}
$

Then I multiply both sides by three to get rid of the fractions, leaving me with

$
3y = 2x - 8
$

But according to the book, the final answer should have a positive eight rather than a negative eight. I'm not sure how to arrive at this answer (something to do with the first step in my working... is there a double negative on the right hand side?). Any help would be appreciated.

2. You just have a simple calculation error when you add 4 to -4/3, 4 = 12/3. 12/3 - 4/3 = 8/3

3. $\displaystyle -\frac{4}{3}+4\Rightarrow -\frac{4}{3}+\frac{12}{3}=\frac{8}{3}$

4. Haha, oops. Guess I was looking too hard. Thanks guys.