The slope intercept equation is y = mx + b
m = slope and b = intercept
m = 1/3
x = -9
y = 5
The equation of a straight line for a given point is
y - y1 = m(x - x1)
y -5 = 1/3(x -(-9))
y -5 = 1/3( x + 9)
Open the parentheses
y -5 = 1/3x + 1 *9 /3
y -5 = 1/3x + 3
Make y the subject of the formula
y = 1/3x + 3 + 5
y = 1/3x + 8
From y = mx + b
Therefore, b = 8
The answer is 8