## xxdgffsdgdfgffgsg 2 years ago Can someone help me graph this equation step by step 1.x^2-6x+8=0

1. qpHalcy0n

First, do you know what basic shape that function makes?

2. xxdgffsdgdfgffgsg

|dw:1364839464696:dw|

3. qpHalcy0n

Right. So the vertex is the lowest (or highest) point on the graph. You can find the x-coordinate of the vertex using -b/2a. Do you know what the a, b, and c terms are?

4. xxdgffsdgdfgffgsg

ok a =1 b=-6 c=8

5. qpHalcy0n

Right, so -b/2a is what?

6. xxdgffsdgdfgffgsg

the answer would be 3 after doing all the steps

7. qpHalcy0n

Well, it means that the vertex is at x=3. To find the corresponding "y" of the vertex, plug 3 in for "x" in the function there.

8. xxdgffsdgdfgffgsg

(3,-1)

9. qpHalcy0n

Okay, so there's your vertex. You know the graph opens up because the quadratic (squared) term is positive. To find where it crosses the x-axis solve the equation for y = 0. It factors nicely: (x +/- ?)(x +/- ?)

10. xxdgffsdgdfgffgsg

so if x is positive it goes up if x is negative it goes down

11. qpHalcy0n

No, if x SQUARED is positive it goes up, (x^2)

12. qpHalcy0n

So how does that function factor. Anything multiply to give 8, but add to give -6?

13. xxdgffsdgdfgffgsg

4 and 2 both are negative

14. qpHalcy0n

Right, so (x - 4)(x - 2). Set each equal to 0 and solve. The solutions will be the x-values where the parabola crosses the x-axis.

15. xxdgffsdgdfgffgsg

ok I understand now thanks for all your help

16. qpHalcy0n

Np, you get those and you have your graph.