Question

How to rewrite the following as f(x)=mx+b

x -y - 5 =0

Answer 1

you want y to be in the place of f(x).

f(x) can basically be seen as a way denote a complex version of y (don't take time to memorise that, haha!). basically, when f(x)=some random number; then y = some random number so.

y=f(x)

i.e f(x) = mx + c
y = mx + c

so taking the equation
y - x - 5 = 0
-y = -x + 5
y = x - 5

Remember that m of mx is the gradient of the line (so it can be equal to 1 in which case we don't write down m) and c is some constant.