SOLUTION: solve using the square root property. 3(x+9)^2-81=0

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: solve using the square root property. 3(x+9)^2-81=0      Log On


   

Question 460093: solve using the square root property. 3(x+9)^2-81=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

3%28x%2B9%29%5E2-81=0 Start with the given equation.


3%28x%2B9%29%5E2=0%2B81Add 81 to both sides.


3%28x%2B9%29%5E2=81 Combine like terms.


%28x%2B9%29%5E2=%2881%29%2F%283%29 Divide both sides by 3.


%28x%2B9%29%5E2=27 Reduce.


x%2B9=%22%22%2B-sqrt%2827%29 Take the square root of both sides.


x%2B9=sqrt%2827%29 or x%2B9=-sqrt%2827%29 Break up the "plus/minus" to form two equations.


x%2B9=3%2Asqrt%283%29 or x%2B9=-3%2Asqrt%283%29 Simplify the square root.


x=-9%2B3%2Asqrt%283%29 or x=-9-3%2Asqrt%283%29 Subtract 9 from both sides.


--------------------------------------


Answer:


So the solutions are x=-9%2B3%2Asqrt%283%29 or x=-9-3%2Asqrt%283%29.