Answer:
y = 4x + 5
Explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Here m = 4, thus
y = 4x + c ← is the partial equation
To find c substitute (1, 9) into the partial equation
9 = 4 + c ⇒ c = 9 - 4 = 5
y = 4x + 5 ← equation of line