how do u find intercepts? math help please?

Question

I was wondering how to find x and y intercepts. i know that u have to set the variable to 0 or someting. can someone help me wth this question please.

f (x) = -3x² + 3

HELP!

Answer 1

Definition of intercept: POINT where a line is on y or x-axis. Y-intercept is on y-axis and x-intercept is on x-axis. The points are ALWAYS (0,_)<--y-intercept or (_,0)<--x-intercept. Remember, the order of the numbers in ordered pairs is (x,y). So if you want to find x-intercept replace f(x) with 9 since f(x)=y.
x-intercept:
0=-3x²+3
-3 -3
-3=-3x²
1=x²
x=1,-1
x-intercept= (1,0) or (-1,0)

y-intercept:
y=-3(0)²+3
y=0+3=3
y-intercept= (0,3)

Answer 2

Remember that the Y-intercept is the value of Y (f(x)) when X=0 (plug 0 in for X and figure out what f(x) is)

Do the same for the X-intercept, but plug 0 in for f(x) and solve

You can also use a graphing calculator too.

Answer 3

Well, in order to find the x intercept y needs to be zero, and vice versa. For your specific problem, [because y=f(x)] to find the x-intercept you would substitute 0 for f(x), making the problem: 0 = 3x² + 3.

To find the y intercept, put a 0 in for the x and solve.

I hope this helps!

Answer 4

ok y intercept is easy. its the b in the mx+b. so in this case its 3

x intercept a little trickier.

one way is -b/m. taking the opposite of b and dividing by m
-3/-3=1.

im not sure the other way where you set it to zero, ill try to figure it out.

edit-
is that x squared? the -b/m might not work, so check by putting the equation in the graphing calculator, go to the tables and look for where y=0, or just estimate based on the graph.

Answer 5

that stuff is hard, tha'ts why im failing math