f(x) = -4x + 3 what is f(-5)

Answer 1

Hi there Jijiuha. When we have a function like this, it's essentially saying "whatever number passed into the function, do to it whatever is on the right side of the equals sign." If we had something like f(x) = x² then f(-5_ would be -5² which is 25. In this problem, we have f(x) = -4x + 3. To find f(-5), we replace x with -5:

f(-5) = -4(-5) + 3

f(-5) = 20 + 3

f(-5) = 23

Hope that helps!

Answer 2

Just substitute -5 for x in the function.

f(-5) = -4(-5) + 3. Be careful with the negative signs!