The problem asks for the equation of a line with the following properties:

• Slope ($m$) = -4
• y-intercept ($b$) = 4

The slope-intercept form of a line is given by the equation:

$y = mx + b$

Substituting the given values into the equation:

$y = -4x + 4$

Thus, the equation of the line is:

$\boxed{y = -4x + 4}$

Would you like further clarification or details on this? Here are some related questions you might find helpful:

1. What is the general form of this line's equation?
2. How do you convert the slope-intercept form to the standard form?
3. What is the significance of the slope in this equation?
4. How can you determine the x-intercept of this line?
5. How can you graph this line given the slope and y-intercept?

Tip: The slope in a linear equation tells you how steep the line is, and a negative slope means the line is slanting downwards.