SOLUTION: Find the quadratic formula online. Solve the formula for c.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Find the quadratic formula online. Solve the formula for c.       Log On


   

Question 1208902: Find the quadratic formula online. Solve the formula for c.
Found 3 solutions by mccravyedwin, ikleyn, timofer:
Answer by mccravyedwin(406) About Me  (Show Source):
You can put this solution on YOUR website!
  

x+%22%22=%22%22+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%5E%22%22%29+

Multiply both sides by 2a to clear the fraction

2ax+%22%22=%22%22+-b+%2B-+sqrt%28+b%5E2-4ac+%29+

Add b to both sides to isolate the radical term

2ax+%2Bb+%22%22=%22%22%22%22+%2B-+sqrt%28+b%5E2-4ac+%29+

Square both sides to eliminate the radical

4a%5E2x%5E2%2B4abx%2Bb%5E2%22%22=%22%22b%5E2-4ac

Add -b2 to both sides

4a%5E2x%5E2%2B4abx%22%22=%22%22-4ac

Divide through by -4a

%284a%5E2x%5E2%29%2F%28-4a%5E%22%22%29%2B%284abx%5E%22%22%29%2F%28-4a%5E%22%22%29%22%22=%22%22%28-4ac%5E%22%22%29%2F%28-4a%5E%22%22%29

Simplify

-ax%5E2-bx%22%22=%22%22c

Add -c to both sides to get 0 on the right

-ax%5E2-bx-c%22%22=%22%220

Multiply through by -1 to minimize negative and minus signs:

ax%5E2%2Bbx%2Bc%22%22=%22%220

which is the general quadratic equation, which is what we always 
start with to derive the quadratic formula.

Edwin

Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!
.
Find the quadratic formula online. Solve the formula for c.
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In a competition for depth of thought, this task might have taken
first place, but from the opposite end.


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comment from student:   Just answer the question.  Nobody is asking for your opinion.


My response:   If you don't care about the expert's opinion,  your game is lost.



Answer by timofer(104) About Me  (Show Source):
You can put this solution on YOUR website!
"Find online" is not necessary and not useful. The solution formula is shown derived in intermediate algebra books.

You just need to be able to start with equation in the form of ax^2+bx+c=0, and to find c, c=-ax^2-bx