## anonymous 5 years ago Solve using the quadratic forumula. 3x^2 + x - 4 = 0

1. anonymous

Do you know the quadratic formula? $-b \pm \sqrt{b ^{2}-4ac}/2a$

2. anonymous

Then it's just a matter of plugging in the values and simplifying.

3. anonymous

3x^2+4x-3x-4=0 (x-1)(3x+4)=0

4. anonymous

x=1,-4/3

5. anonymous

I understand how to substitute everything in, but from there I am unsure how to simplify -1 ± 12−4*3*4−−−−−−−√

6. anonymous

-1 +/- sqrt -48

7. anonymous

a=3,b=1, c=-4

8. anonymous

Work on the square root part first. $\sqrt{1^{2}-4*3*-4}$

9. anonymous

You missed a couple things in the sqrt. $1^{2}=1$ 4*3*-4=-48 1-(-48)

10. anonymous

Get that? So it's $\sqrt{1+48}=\sqrt{49}=7$ So, $(1 \pm 7)/6$

11. anonymous

Thank you very much! That makes much more sense now. Once again, thanks!

12. anonymous

np.