Let's take a look at the straight line y = ( 2/3 ) x – 4. Its graph looks like this: To find theslope, we will need two points from the line. Pick two x's and solve for each corresponding y: If, say, x = 3, then y = ( 2/3 )(3) – 4 = 2 – 4 = –2.
In your example, the equation is in y=mx+b, where m is the slope.  2/3 is the slope.  No need to find the values of x and y on the line, as the slope-intercept form y=mx + b, the slope is the value of "m".
use the formula y= mx+ b
in general form: Ax+By+C=0 and in standard form: Ax+By=C.