SOLUTION: Solve: 10x^2 = 20x+30 What are the solutions to the equation? Can someone please help me with this? Thanks

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve: 10x^2 = 20x+30 What are the solutions to the equation? Can someone please help me with this? Thanks      Log On


   

Question 438421: Solve:
10x^2 = 20x+30
What are the solutions to the equation?
Can someone please help me with this? Thanks
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+10x%5E2+=+20x+%2B+30+
Subtract 20x from both sides
+10x%5E2+-+20x+=+30+
Divide both sides by 10
+x%5E2+-+2x+=+3+
Now you can complete the square.
Take 1/2 of the coefficient of x,
square it, and add it to both sides
+x%5E2+-+2x+%2B+%28-2%2F2%29%5E2+=+%28-2%2F2%29%5E2+%2B+3+
+x%5E2+-+2x+%2B+1+=+1+%2B+3+
Both sides are now a perfect square
+%28+x+-+1+%29%5E2+=+2%5E2+
Take the square root of both sides
+x+-+1+=+2+ ( this is the (+) square root)
+x+=+3+
and
+x+-+1+=+-2+ (this is the (-) square root)
+x+=+-1+
The solutions are x=3 and x=-1