Respuesta :

Answer:

y = m x + b     equation of straight line

Slope = (y2 - y1) / (x2 - x1) = (-3 - 1) / ((7 - (-5)) = -4 / 12 = -1 / 3

y = -x / 3 + b       since m is defined above

lf y = 7 then x = -5     given

7 = 5/3 + b  

b = (21 - 5) / 3 = 16 / 3 = 5 1/3

y = -x / 3 + 5 1/3

Check:   Use point x = -5

y = 5/3 + 16/3 = 21 / 3 = 7      correct