- Slope-Intercept Form: y = mx + b, with m = slope and b = y-intercept.
If two lines are perpendicular, then they will have slopes that are <u>negative reciprocals</u> to each other. An example of negative reciprocals are 2 and -1/2
<h2>6.</h2>
Now with line 2, I have to convert it to slope intercept form. Firstly, subtract 2x on both sides of the equation: 
Next, divide both sides by -5 and your slope-intercept form is 
Now since 2/5 is <em>not</em> the negative reciprocal of -2/5, <u>these lines are not perpendicular.</u>
<h2>7.</h2>
It's pretty much the same process; convert to slope-intercept and determine if negative reciprocal. This time I'll brush through them:

Now since 2 <em>is</em> the negative reciprocal of -1/2, <u>these lines are perpendicular.</u>