Question

Which equation is in slope-intercept form and represents a line with slope 3 through the point (9, –4)?

Answer 1

The slope-intercept form of a line is:

$y = mx + q$

Where m is the slope and y is the y-intercept:

$y = 3x + q$

To find q (y-intercept), substitute the coordinates of the point (9, -4) in the equation of the line and solve it as an equation:

-4=3(9)+q
-4=27+q
q=-27-4=-31

The equation of the line is: y=3x-31