Question

Its been a a year or 2 since I have takin math. How do you do equations (y=3x-3). I can't really explain, but just explain anything that has this.

Answer 1

y=3x-3
is the equation of a line

people learn to plot lines on graph paper
how to find y if they know x. for example, if x is 0, then y = 3*0-3 or just y= -3

people learn that the "slope" is 3
and the "y-intercept" is -3

Answer 2

Ok so can you please explain f(x) things.?

Answer 3

when people write f(x) that is short for:

there is a rule (we name it "f"), that tells us how to calculate an answer that depends on "x"

x is a "place-holder" in the rule, and is replaced by a number when we do the calculation

Answer 4

for example,
say we have

f(x) = x+1

the rule (named "f") says: given a number add 1 to it

f(1) is how we say what number we want to start with:
f(1) = 1+1 (we replace the x with 1)
f(1) = 2

that means when we use rule f with x=1 we get 2 as our answer.

Answer 5

Thank you so much @phi. You are my hero ! :) <3

Answer 6

people usually call f a "function" instead of a rule
but it means pretty much the same thing. But to keep things simple, a function (or rule) is only allowed to give one number for each x

Here is a rule that is not a function:
sqrt(x)

that is not a function because sqr(4) = 2 or sqr(4) = -2 (both -2 and 2 work)
but we are not allowed to have two different answers. so f(x) = sqr(x) is not allowed
(unless we say: only the positive values are allowed... then we can use it as a function)