You can write the equation using Point Slope form
Given point (x1,y1) and slope m, the equation would be
y-y1 = m(x-x1)
Plug in the values for (x1, y1)= (3,3) and slope m = 4/3 in the above equation. Simplify by using distributive property (multiply each term inside the parentheses by the slope 4/3) and solve
Hope you will be able to do this from here.