Question

what is the y-intercept of the function $f(x) = 4 - 5x$?
options: -4, 4, -5, 5

Explanation:

Step1: Recall the slope - intercept form

The slope - intercept form of a linear function is \(y = mx + b\), where \(m\) is the slope and \(b\) is the \(y\) - intercept. When \(x = 0\), \(y=b\), which is the value of the function at \(x = 0\), and this gives the \(y\) - intercept.

Step2: Rewrite the given function

The given function is \(f(x)=4 - 5x\), which can be rewritten in the slope - intercept form as \(f(x)=- 5x + 4\).

Step3: Find the \(y\) - intercept

Comparing \(f(x)=-5x + 4\) with \(y=mx + b\), we can see that when \(x = 0\), \(f(0)=-5\times0 + 4=4\). So the \(y\) - intercept is \(4\).

Answer:

4 (corresponding to the option with value 4)