SOLUTION: Give exact and approximate solutions to three decimal places (x+9)^2 = 20?

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Question 525873: Give exact and approximate solutions to three decimal places (x+9)^2 = 20?
Found 2 solutions by Tatiana_Stebko, jim_thompson5910:
Answer by Tatiana_Stebko(1539) About Me  (Show Source):
You can put this solution on YOUR website!
%28x%2B9%29%5E2+=+20
x%2B9=sqrt%2820%29, or x%2B9=-sqrt%2820%29
x%5B1%5D=-9%2Bsqrt%2820%29, x%5B2%5D=-9-sqrt%2820%29 the exact solutions
x%5B1%5D=-4.528, x%5B2%5D=-13.472%29 the approximate solutions to three decimal places

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

%28x%2B9%29%5E2=20 Start with the given equation.


x%2B9=%22%22%2B-sqrt%2820%29 Take the square root of both sides.


x%2B9=sqrt%2820%29 or x%2B9=-sqrt%2820%29 Break up the "plus/minus" to form two equations.


x%2B9=2%2Asqrt%285%29 or x%2B9=-2%2Asqrt%285%29 Simplify the square root.


x=-9%2B2%2Asqrt%285%29 or x=-9-2%2Asqrt%285%29 Subtract 9 from both sides.


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Answer:


So the exact solutions are x=-9%2B2%2Asqrt%285%29 or x=-9-2%2Asqrt%285%29.


which approximate to x=-4.528 or x=-13.472


Note: use a calculator to find the approximations