## Janu16 one year ago Given the equation Square root of 8x plus 1 = 5, solve for x and identify if it is an extraneous solution.

1. Janu16

|dw:1438822086628:dw| so i checked my answer and i got 2 but thats not one of my answer choice

2. Janu16

@DanJS

3. DanJS

hi

4. DanJS

if that 1 is under the root , you cant just subtract it

5. DanJS

square both sides first 8x + 1 = 25

6. Janu16

how did you get 25

7. DanJS

squared both sides first, removes the root, and 5^2 = 25

8. Janu16

oh so you solve the whole thing

9. DanJS

you subtracted a 1 out from underneath the root sign, that is illegal

10. Janu16

ohok lol

11. Janu16

so you get 3

12. DanJS

$[\sqrt{8x+1}]^2=5^2$

13. DanJS

yeah 3

14. Janu16

thx

15. DanJS

np