The general equation of a line is
y= ax + b
where a is the slope
So a = -7
So y= -7x + b
But it passes through the point (5, -3)
Substitute the coordinates to calculate b:
So -3 = -7(5) + b
-3 = -35 + b
b= 35-3
b= 32
So the equation of the line of slope -7 and passing through the point (5, -3) is
y= -7x + 32