## BloomLocke367 one year ago Help with Pre-Cal?

1. jdoe0001

posting specifics helps

2. BloomLocke367

It says to solve algebraically and confirm graphically, and the first problem is $$v^2-5=8-2v^2$$

3. BloomLocke367

I was getting there, lol XD

4. jdoe0001

$$\bf v^2-5=8-2v^2\implies v^2+2v^2=8+5\implies v=?$$

5. triciaal

put the variables on one side constants on the other keep the balance of the equation

6. BloomLocke367

When I solved aglebraically I got $$v=\sqrt{\frac{13}{3}}$$

7. BloomLocke367

But when I graphed it, I don't think it's right... but I may have made an error. That's why I'm asking for help.

8. BloomLocke367

oops, I meant to say when I graphed it, it didn't match my algebraic solution.

9. jdoe0001

notice, is a quadratic equation, 2nd degree polynomial, thus 2 answers $$\bf v^2-5=8-2v^2\implies v^2+2v^2=8+5\implies v=\pm\sqrt{\cfrac{13}{3}}$$

10. BloomLocke367

I forgot to put that, but I know that. lol

11. jdoe0001

hmmm ok.... so.. whathmm how did you do the graph anyway? just a table of values?

12. BloomLocke367

I set the equations equal to zero

13. BloomLocke367

and used a calculator

14. BloomLocke367

equation**

15. jdoe0001

so.... I'd think... the graph is ok...no?

16. BloomLocke367

obviously, I got a parabola with the y-intercept -13. And my zeroes were $$\pm$$2.082

17. BloomLocke367

Is that correct?

18. jdoe0001

$$\bf \pm\sqrt{\cfrac{13}{3}}=\pm2.08166599946613273528$$ so, the zeros look fine

19. BloomLocke367

ohhhh... so I was right, sorry. I was thinking of something else when I graphed it and that was my problem lol

20. BloomLocke367

Thanks *facepalm*

21. triciaal

|dw:1440630977887:dw|

22. BloomLocke367

Thanks!

23. jdoe0001

http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIzeF4yLTEzIiwiY29sb3IiOiIjMDAwMDAwIn0seyJ0eXBlIjoxMDAwLCJ3aW5kb3ciOlsiLTguMzQ5OTk5OTk5OTk5OTk4IiwiNy45IiwiLTEzLjU1MDAwMDAwMDAwMDAwMiIsIi0zLjU0OTk5OTk5OTk5OTk5OSJdfV0- drag the graph down, to see the intercepts anyhow, you can zoom in/out by using the mouse middle-button so those are the intercepts

24. BloomLocke367

yeah, I have the graph right in front of me. I was just thinking I was looking for something else, I don't know why. XD

25. jdoe0001

In every work of genius we recognize our own rejected thoughts: they come back to us with a certain alienated majesty. ~~ Ralph Waldo Emerson ~~

26. BloomLocke367

Very wise. I have another one, but I think I need to use completing the square to do it.. Can you maybe help?

27. jdoe0001

sure, post anew, more eyes :)