A. In order to find the equation, first we need to find the slope

m is the slope
(-4, -1)=(x1,y1)
(-9,-5)=(x2,y2)
we substitute the values

then we use the point-slope form

we substitute the values

B. in order to find the slope-intercept form we need to isolate the y

C. if the y coordinate is 7

then we isolate the x


the value of the x-coordinate is 6 when the y-coordinate is 7