SOLUTION: Find the smallest value of x such that x^2 + 10x + 25 = -x^2 + 5x + 32.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Find the smallest value of x such that x^2 + 10x + 25 = -x^2 + 5x + 32.      Log On


   



Question 1209249: Find the smallest value of x such that x^2 + 10x + 25 = -x^2 + 5x + 32.
Found 2 solutions by Edwin McCravy, ikleyn:
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2+%2B+10x+%2B+25+=+-x%5E2+%2B+5x+%2B+32
2x%5E2+%2B+5x+-+7+=+0
%282x%2B7%29%28x-1%29=0
2x+7=0;     x-1=0
  2x=7;       x=1
   x=7/2
   x=3.5

Since 1 is smaller than 3.5, the answer is 1

Duh!

Edwin


Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
Find the smallest value of x such that x^2 + 10x + 25 = -x^2 + 5x + 32.
~~~~~~~~~~~~~~~~~~~~~~~~


                                        Step by step

              Step 1.  Reduce to the standard form quadratic equation


For it, collect all the terms in the left side and combine like terms.
You will get

    2x^2 + 5x - 7 = 0.



              Step 2.  Calculate the discriminant to determine if the roots are real


d = b^2 - 4ac = 5^2 - 4*2*(-7) = 25 + 56 = 81.


The discriminant is positive, so the roots are real numbers, 
and we can use the conception "greater-smaller" for them.



              Step 3.  Use the quadratic formula to find the smallest root


smallest root = %28-b+-+sqrt%28d%29%29%2F%282a%29 = %28-5+-+sqrt%2881%29%29%2F%282%2A2%29 = %28-5+-+9%29%2F4 = %28-14%29%2F4%29 = -31%2F2 = -3.5.    ANSWER  

Solved.