## kirk.freedman Group Title Use the quadratic formula to solve the equation. x^2 – 7x – 6 = 0 Show work please. one year ago one year ago

1. winterfez Group Title

x^2-7x-6=0?

2. lilg132 Group Title

$x = \frac{ -b \pm \sqrt{b ^{2} -4ac} }{ 2a}$

3. kirk.freedman Group Title

yes it is an exponent

4. lilg132 Group Title

x2 = a -7x = b -6 = c x2 = 1 -7x = -7 -6 = -6

5. tcarroll010 Group Title

$x = \frac{ -b \pm \sqrt{b ^{2}-4ac} }{ 2a }$where a=1, b=-7, and c =-6 This is because your equation is in the standard form of ax^2 + bx + c = 0. So, now, just make the substitutions.

6. kirk.freedman Group Title

Hmm, ok thanks, let me work this out and I will reply to what I got to check if it is right.

7. tcarroll010 Group Title

Hint: after you make your substitutions, pay special attention to the expression within the radical (the square root sign). You will see that the numbet in the radical is positive, so you will have two real solutions. But your final solution will have a radical in it.

8. winterfez Group Title

|dw:1354234621716:dw|

9. tcarroll010 Group Title

Are you able to identify the variables a, b, and c and make the substitutions?

10. kirk.freedman Group Title

Yes, I got to the step that winterfezz last showed, but I don't know what to do now

11. tcarroll010 Group Title

12. winterfez Group Title

13. tcarroll010 Group Title

And when you have a negative number times a positive number, the product will be negative.

14. tcarroll010 Group Title

So, can you determine (-7)^2 ?

15. tcarroll010 Group Title

(-7)^2 is the same as (-7)(-7) and that is the same as (7)(7)

16. kirk.freedman Group Title

Yes, tcarroll, I know all that basic math stuff xD I am at the part where I have |dw:1354235055422:dw|

17. tcarroll010 Group Title

18. kirk.freedman Group Title

So I do not simplify it further?

19. tcarroll010 Group Title

That's as far as you can take it.

20. tcarroll010 Group Title

It is customary to leave it with the +- sign

21. kirk.freedman Group Title

Ok, so no decimal needed, I just leave it as this?

22. tcarroll010 Group Title

That's good just like that.

23. kirk.freedman Group Title

Thank both of you very much!:)

24. tcarroll010 Group Title

$\frac{ 7\pm \sqrt{73} }{ 2 }$Like that

25. tcarroll010 Group Title

You're very welcome!