The line with equation y + ax = c passes through the points (1,5) and (3,1). Find a and c

Answer 1

I would first find an equation for the line in point-slope form: y-y₁=m(x-x₁). m is the slope and be found by doing (y₂-y₁)/(x₂-x₁). (1-5)/(3-1)= -2=m. Then just use the point (3,1) for y₁ and x₁ in the equation above.

y-1=-2(x-3), then just move around the variables and constants to find the given form, y+ax=c.

y+2x=7, so a=2 and c=7.