Find the equation of the line through (-8, 9) with x-intercept trice the y-intercept.

Answer 1

(x,0), (-8,9), (0,y). X = 3y,
(3y,0), (-8,9),(0,y).

m = (9-0)/(-8-3y) = (y-9)/(0+8), 72/(-8-3y) = y-9, -8y-3y^2+72+27y = 72, -3y^2+19y = 0,

y(-3y+19) = 0, Y = 0, -3y+19 = 0, 3y = 19, X = 3y = 19, Y = 6 1/3 = 19/3.

m = 9/(-8-19) = -1/3.

Y = mx + b = 9, (-1/3)(-8) + b = 9, b = 9-8/3 = 19/3 = 6 1/3.

Eq: Y = -x/3 + 19/3.