Question

Mathematics challenge

Answer 1

Get the equation of the line containing PQ using the point-slope formula:

y - (-2) = 3/2 (x - (-6))

Solve for y to get it in slope-intercept form:

y = 3/2 x + 7

so the y-intercept is (0, 7).

The line containing QR is then

y - 7 = -3/4 (x - 0)

or

y = -3/4 x + 7

The point R is on the x-axis, so its y-coordinate is 0. Plug in y = 0 and solve for x to get the other coordinate:

0 = -3/4 x + 7

3/4 x = 7

x = 4/3×7 = 28/3

So the point R has coordinates (28/3, 0).