Video Transcript
Find the coordinates of the point
where 𝑦 equals four 𝑥 plus 12 intersects the 𝑦-axis.
So in this question, we’re given
the equation of a straight line in slope-intercept form. And we’re asked for the coordinates
of the point where it intersects the 𝑦-axis. What this question is checking then
is do we understand slope-intercept form and what the different parts of the
equation represent. Remember that slope-intercept form
is 𝑦 equals 𝑚𝑥 plus 𝑐, where 𝑐 represents the 𝑦-intercept of the straight
line, which is what we’re looking for here. The 𝑦-intercept is the point where
the line intersects the 𝑦-axis. So we can see by comparing the
general form and the specific straight line that we have, the value of 𝑐 here is
12.
But the question doesn’t just ask
us for the value of 𝑐; it asks us for the coordinates of this point. So the 𝑦-intercept remember is a
point on the 𝑦-axis. We’ve just worked out its
𝑦-coordinate; it’s this value of 12. To work out the 𝑥-coordinate, we
just need to remember that at every point on the 𝑦-axis the 𝑥-coordinate is
zero. You could perhaps see this more
clearly by picturing what the graph would look like as I’ve done here. So the coordinates of this point
then are going to be zero, 12. And that is our final answer to
this question.
