So, we will be using point-slope form to construct this equation.
Point-slope form's general formula is as follows:

M is the slope,
Y₁ is the Y-coordinate of the point
X₁ is the X- coordinate of the point.
So, our slope is 3 (since the equation is given in slope-intercept form)
Our Y₁ is 7 and out X₁ is 4
So, now we just plug our numbers into the equation.

There's your equation.
Hope this helps!