Someone help please I don’t understand how to do this. I need the y intercept x intercept and f(15) and f(?)=12.44

In order to find the y-intercept you have to plug in 0 for x in the equation, so:
f(0) = -1.4(0) - 15
When you solve, you would get y-intercept = -15
In order to find the x-intercept you have to set the equation equal to 0, so:
0 = -1.4x - 15
Solve for x and you would get -10.714...
f(15) = -1.4(15) - 15
f(15) = -36
-1.4x - 15 = 12.44
Add 15 to both sides
-1.4x = 27.44
Divide both sides by -1.4
x = -19.6