SOLUTION: Ok so in algebra today we learned like 2 days ago the QUADRATIC FORMULA...well i just dont understand how to solve it. for ex. {{{3x^2+4x-8=0}}} I dont understand how to do the

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Ok so in algebra today we learned like 2 days ago the QUADRATIC FORMULA...well i just dont understand how to solve it. for ex. {{{3x^2+4x-8=0}}} I dont understand how to do the      Log On


   

Question 417052: Ok so in algebra today we learned like 2 days ago the QUADRATIC FORMULA...well i just dont understand how to solve it. for ex.
3x%5E2%2B4x-8=0
I dont understand how to do the steps to get the answer
so i do x=-4+/-=sqrt (4)^2-4(3)(-8)
then x= +/-+sqrt 16-96/ 2x3
i dont know where to go from there.
Found 2 solutions by checkley79, Earlsdon:
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
3x^2+4x-8=0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x=(-4+-sqrt[4^2-4*3*-8])/2*3
x=(-4+-sqrt[16+96])/6
x=(-4+-sqrt112)/6
x=(-4+-10.583)/6
x=(-4+10.583)/6
x=6.583/6
x=1.097 ans.
x=(-4-10.583)/6
x=-14.853/6
x=-2.43 ans.

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
It's not nearly as complicated as you make it seem.
The formula is:
x+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a
To solve for x in: 3x%5E2%2B4x-8+=+0 Substitute into the formula: a = 3, b = 4, and c = -8 as you did already.
x+=+%28-4%2B-sqrt%284%5E2-4%283%29%28-8%29%29%29%2F2%283%29 Now simplify his lot.
x+=+%28-4%2B-sqrt%2816-%28-96%29%29%29%2F6
x+=+%28-4%2B-sqrt%28112%29%29%2F6 Now simplify the square root.
x+=+%28-4%2B-sqrt%2816%2A7%29%29%2F6 sqrt%2816%29+=+4 so put the 4 in front of the radical leaving the 7 inside.
x+=+%28-4%2F6%29%2B%284%2F6%29sqrt%287%29 and x+=+%28-4%2F6%29-%284%2F6%29sqrt%287%29 Simplify the fractions.
x+=+%28-2%2B2sqrt%287%29%29%2F3 and %28-2-2sqrt%287%29%29%2F3