## OwlEyes 3 years ago Which of the following is the solution to the equation 25(z + 2) = 125 ? z = 5.5 z = 3.5 z = -2.5 z = -0.5

1. mahmit2012

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2. OwlEyes

3 isnt an option

3. thejoshfish

just solve the equation.. it's not that hard.

4. OwlEyes

is 3.5?

5. mahmit2012

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6. thejoshfish

test it. 3.5+2=5.5 5.5(25)=137 so no

7. sputnik

I would start by multiplying the equation out. 25z + 50 = 125. Then I would solve for z. First isolate it: 25z = 75 And then divide by 25. z = 3.

8. OwlEyes

3 is not an option

9. thejoshfish

well your math book is wrong then.

10. OwlEyes

No i wrote it wrong!! lol Its: 25^(z+2)=125

11. sputnik

You need to take the log of both sides then solve for z..

12. OwlEyes

how do i do that?

13. sputnik

It looks like this: 2 * ln(5) * z + 4 * ln(5) = 3 * ln(5)

14. OwlEyes

I dont know what that means??

15. sputnik

And to finish it up as in actually compute it you need to use a calculator because the decimals are messy. 3.21 * z + 6.43 = 4.82 And solve for z.

16. sputnik

You will get z = -0.5. Is that one of the options?

17. OwlEyes

Yepp:)) Thanks sooo much!

18. sputnik

No prob. Thanks for the medal. And for the logs, on the right hand side, 125 = 5 ^ 3. so it equals 3 * ln(5). The exponent out front and the log of what the exponent worked on.

19. OwlEyes

Ohhh gotcha! Thanks again and you deserve it:)