(-5,-1)(10,-7)
slope = (-7 - (-1) / (10 - (-5) = -6 / 15 reduces to -2/5
y - y1 = m(x - x1)
slope(m) = -2/5
(10,-7)...x1 = 10 and y1 = -7
sub
y - (-7) = -2/5(x - 10) =
y + 7 = -2/5(x - 10)...point slope form
y + 7 = -2/5x + 4
y = -2/5x + 4 - 7
y = -2/5x - 3 ...slope intercept form
2/5x + y = -3
2x + 5y = -15 <== standard form