SOLUTION: Solve for x using the quadratic formula: f(x) = -3x2 + x + 1

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve for x using the quadratic formula: f(x) = -3x2 + x + 1      Log On


   

Question 1204349: Solve for x using the quadratic formula:
f(x) = -3x2 + x + 1
Found 2 solutions by ikleyn, MathLover1:
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

Learn how to use the quadratic formula from these lessons
    - Introduction into Quadratic Equations
    - PROOF of quadratic formula by completing the square
in this site.

Then solve the equation on your own.


It is YOU, who needs this exercise - not me.



Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

f%28x%29+=+-3x%5E2+%2B+x+%2B+1

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
in your case a=-3, b=1, and c=1

x+=+%28-1+%2B-+sqrt%28+1%5E2-4%2A%28-3%29%2A1+%29%29%2F%282%2A%28-3%29%29+

x+=+%28-1+%2B-+sqrt%28+1%2B12+%29%29%2F%28-6%29+
x+=+%28-1+%2B-+sqrt%28+13+%29%29%2F%28-6%29+

solutions:

x+=++1%2F6+%2Bsqrt%2813%29%2F6+
or
x+=++1%2F6+-+sqrt%2813%29%2F6+