the equation of a linear function is in the form y=mx+c. where m is the slope, c the y-intercept and x the independent.
So given coordinates of a point on the line we can find its equation by substituting the given values in the general equation.
for x replace with the x-coordinate and do the same for y. it becomes:
1 = 7(-5) + c
c = 36
hence: y = 7x +36
