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## anonymous one year ago Check my answers again Lol please Find the number of real number solutions for the equation. x^2-15=0 1 0 2 - my answer Can not be determined from the graph

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1. dinamix

are u sure its x^2-15=0 o.O ?

2. anonymous

Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth. A rocket is launched from atop a 101-foot cliff with an initial velocity of 116 ft/s. a. Substitute the values into the vertical motion formula h = -16t^2 + vt + c. Let h = 0 b. Use the quadratic formula find out how long the rocket will take to hit the ground after it is launched. Round to the nearest tenth of a second. A) 0 = -16t^2+101t+116; 8s B) 0 = -16t^2+116t+101; 0.8s - my answer C) 0 = -16t^2+101t+116; 0.8s D) 0 = -16t^2+116t+101; 8s

3. phi

$x^2-15=0 \\ x^2= 15 \\ x= \pm \sqrt{15}$ you would not get real number solutions if you had to take the square root of -15 but here, you have two real numbers.

4. anonymous

wait a min let me recheck

5. anonymous

Yeah @dinamix

6. dinamix

cuz i find answer like @phi

7. phi

you have the correct equation, but if we used t=1 (which is close to t=0.8) we get -16+116+101 which is not close to zero (we want height = 0 when on the ground)

8. anonymous

I don't get it, are my answers wrong..

9. anonymous

can you help me @ASAAD123

10. anonymous

@pooja195

11. anonymous

and one more question Use any method to solve the equation. If necessary, round to the nearest hundredth. 7x^2-16x=8 0.42, –2.71- my answer 35.43, –33.14 5.42, –2.95 2.71, –0.42

12. anonymous

the first one is correct. The equation is correct for the second one. The solution isn't. The third one is wrong

13. anonymous

I wasn't sure.. for the second one I was like either B or C are both wrong.. if not B then C, not sure tho @peachpi

14. anonymous

the equation you selected is the right one, but 0.8 isn't a solution to it. Check to see that you plugged the numbers into the quadratic equation correctly.

15. anonymous

the third one is it D?

16. anonymous

@peachpi

17. anonymous

@Luigi0210

18. anonymous

Can someone helpp meee

19. anonymous

which question?

20. anonymous

and one more question Use any method to solve the equation. If necessary, round to the nearest hundredth. 7x^2-16x=8 0.42, –2.71- my answer 35.43, –33.14 5.42, –2.95 2.71, –0.42 - my answer

21. anonymous

D

22. anonymous

not A

23. anonymous

so we are trying to find solution to $7x^{2}-16x=8$ ?

24. anonymous

so which method did you use to solve this question?

25. anonymous

you could use, graphical methods, quadratic formula, etc..

26. anonymous

yes D

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