## anonymous 5 years ago Please help...Use the quadratic and a calculator to solve the following equation. Round intermediate calculations and final answers to two decimal places. 6.25y^2 + 12y + 5.76 = 0 i got y = .96, -96 but it was wrong should i round up to 1, -1

1. anonymous

if you require the answer correct to dec places to do not iround intermediate results to 2 dp's

2. anonymous

right so I dont understand the statement Round intermediate calculations and final answers to two decimal places

3. anonymous

2 dec places i meant to say

4. anonymous

Is it bcuz it is saying Use the quadratic and a calculator to solve

5. anonymous

i make the solutios -0.96

6. anonymous

there is only one solution

7. anonymous

so you think incluce the 0

8. anonymous

can a solution set have only one thing in it?

9. anonymous

yes

10. anonymous

6.25y^2 + 12y + 5.76 = 0 Rationalize the coefficients. $\frac{25}{4}y^2+12y+\frac{144}{25}=0$Multiply each side by 100 and simplify.$625 y^2+1200 y+576=0$Use the binomial theorem or, to pull a rabbit out of the hat:$625 y^2+1200 y+576=(25 y+24)^2$$y=\frac{24}{25}\text{ }\text{or}\text{ }0.96$

11. anonymous

if you graph this function it will just touch the x axis at -0.96

12. anonymous

I stand corrected. Yes, the sign is negative. Thank you.

13. anonymous

ok

14. anonymous

so you are saying that the only solution in the solution set is -0.96??

15. anonymous

There are two solutions, each with identical values.

16. anonymous

so both would be -0.96

17. anonymous

yes

18. anonymous

but I probably only need to enter it once?

19. anonymous

the books always say two identical solutions but to be honest i dont understand why

20. anonymous

Woohoo it was correct...thank you both sooooo much!!!

21. anonymous

I use Mathematica to do the calculations.$\text{Solve}\left[(25 y+24)^2\text{==}0,y\right]=\left\{\left\{y\to -\frac{24}{25}\right\},\left\{y\to -\frac{24}{25}\right\}\right\}$Notice that it returned two values for y. I would put down as an answer, x = -0.96 twice. Does this answer you questions?

22. anonymous

no probs popcorn

23. anonymous