(13,-5), (-6, 8)

Question

I don't know how to de these

Answer 1

I guess you want the equation of the line joining these points.

The general equation for a line is y=mx+a where m is the slope of the line and a is the y intercept (where the line cuts the y axis). The slope m=(difference between y coord)/(difference between x coord)=

m=(8-(-5))/(-6-13)=13/(-19)=-13/19. This means the line slopes backwards. 

So we now have y=-(13/19)x+a. To find a we plug in one of the points: x=-6, y=8:

8=-(13/19)(-6)+a; 8=78/19+a; 8-78/19=a.

a=(152-78)/19=74/19, so y=(74-13x)/19.