SOLUTION: My question states: x^2+3x+c Find the value of c that makes the trinomial a perfect square. I tried several different ways to figure it out and each way was wrong :(

Algebra ->  Square-cubic-other-roots -> SOLUTION: My question states: x^2+3x+c Find the value of c that makes the trinomial a perfect square. I tried several different ways to figure it out and each way was wrong :(      Log On


   

Question 1090244: My question states:
x^2+3x+c
Find the value of c that makes the trinomial a perfect square.
I tried several different ways to figure it out and each way was wrong :(
Found 2 solutions by ikleyn, MathLover1:
Answer by ikleyn(52921) About Me  (Show Source):
You can put this solution on YOUR website!
.
Did you try c = %283%2F2%29%5E2 = 2.25 ?


On completing the square see the lessons
    - Introduction into Quadratic Equations
    - PROOF of quadratic formula by completing the square

    - HOW TO complete the square - Learning by examples
in this site.


Also, you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook under the topic "Quadratic equations".



Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2%2B3x%2Bc
recall the rule:%28a%2Bb%29%5E2=+a%5E2%2B2ab%2Bb%5E2
so, c=b%5E2
since a=1 and
2ab=3 -> b=3%2F2
then, since c=b%5E2 we have
c=%283%2F2%29%5E2
c=9%2F4