You can first put this equation into slope-intercept form (also known as y=mx+b form). You do that by using your algebra skills to get y on one side and everything else on other side of the equal sign and put it in this form.
First, you should subtract the 2x from both sides. Resulting in:
-10y = 30 - 2x
Then to get the y by itself, you should divide both sides by -10. Resulting in:
y = -3 + 0.2x = 0.2x - 3
In slope-intercept form, the m in y=mx+b is the value of the slope and the m is the coefficient or the constant that goes before the x variable. In this case, the m-value is 0.2. Therefore, the slope is 0.2.