Question

How do i find where a function intersects the X axis

Answer 1

Remember that y=f(x), therefore saying y=0 is saying f(x)=0. So you just need to find x such that x3+x2−x−1=0. To do this first inspect for pretty numbers like small (in absolute value) integers.

Answer 2

When does the graph intersect the y-axis? Exactly when x=0. And when does it intersect the x-axis? Exactly when f(x)=0.

Answer 3

That flew over my head but the example is 3x+8y=12

Answer 4

find the x intercept.....by solving f(x) = 0

Answer 5

make y the subject first

Answer 6

Now let's confirm this fact algebraically:

Find the intersection with the x-axis. Set y=0, that is f(x)=0. So you're trying to find x such that x3+x2−x−1=0, which is equivalent to (x−1)(x+1)2=0. So you get x=1 and x=−1 as roots of the equation. Since y=0, you get the intersecting points (−1,0) and (1,0), as expected.
Find the intersection with the y-axis. Set x=0. You get f(0)=y which is equivalent to −1=y. Therefore the point in which the graph of the function intersects the y-axis is (0,−1).

Answer 7

I can help you with the problem Benjamin

Answer 8

Thanks, would the answer be x=4

Answer 9

Yes

Answer 10

I just used the Coverup method

Answer 11

Ok is this your question? 3x-8y=12

Answer 12

If so, I can help you with an easier technique