The general equation of a straight line is given as:
y = mx + c
Where:
y = the function of x (the dependent variable)
x = the independent variable
m= the slope of the straight line
c = the y-intercept of the straight line
Now, given the function: f(x) = 4x - 5, when we compare this with the general equation shown earlier, we can say that:
y = f(x)
x = x
m= 4
c= -5
Therefore the y-intercept of the straight line is -5