<p>Lines p and q are perpendicular, and intersect at
the point (-7, 3). The slope of line p is numerically
equal to the y-coordinate of the y-intercept of
line p. What is the y-coordinate of the y-intercept
of line q ?</p>
<p>If you take the equation of line p to be y=mx+m, then substitute the coordinate of the intersection. You’ll get m= -1/2. This means that the gradient of line q = 2. And so y=2x+c. Substitute the values of the point of intersection. c = -11</p>
<p>the answer is 17 accdg to PR …</p>
<p>if you follow his steps you will get 17. he simply computed the last step wrong.</p>
<p>oh, right 
thanks!</p>
<p>AND THIS IS HOW I LOSE POINTS IN MY SAT!! CARELESSNESS!! :o</p>