SOLUTION: Hello, I have a question relating to the application of the quadratic formula on the following problem: (d-12)=(d) - 2 The (d-12) and (d) are under a radical, but the -2 is n

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Question 122858This question is from textbook prentice hall algebra 2 with trigonometry
: Hello, I have a question relating to the application of the quadratic formula on the following problem:
(d-12)=(d) - 2
The (d-12) and (d) are under a radical, but the -2 is not.
I tried this a few ways, but cannot get the answer 16 from the back of the book.
I really appreciate your assistance on this and thank you in advance. This question is from textbook prentice hall algebra 2 with trigonometry

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for d:
sqrt%28d-12%29+=+sqrt%28d%29-2 Square both sides.
d-12+=+d-4sqrt%28d%29%2B4 Subtract d from both sides.
-12+=+-4sqrt%28d%29%2B4 Subtract 4 from both sides.
-16+=+-4sqrt%28d%29 Divide both sides by -4
4+=+sqrt%28d%29 Finally, square both sides.
16+=+d