SOLUTION: Basically it asks to solve by using the quadratic forumla, by leaving irrational roots in the simplest radical form. The problem is 3x^2-4x-5=0 The trpuble I am having with this

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: Basically it asks to solve by using the quadratic forumla, by leaving irrational roots in the simplest radical form. The problem is 3x^2-4x-5=0 The trpuble I am having with this       Log On


   

Question 147229This question is from textbook algebra
: Basically it asks to solve by using the quadratic forumla, by leaving irrational roots in the simplest radical form.
The problem is 3x^2-4x-5=0
The trpuble I am having with this is solving it, I tried doing the problem by using the quadratic formula, but I get frustrated in the middle of the problem. I get stuck. Thank You if you are willing to take the time to help me=) This question is from textbook algebra

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


x+=+%28-%28-4%29+%2B-+sqrt%28+%28-4%29%5E2-4%283%29%28-5%29+%29%29%2F%282%283%29%29 Plug in a=3, b=-4, and c=-5


x+=+%284+%2B-+sqrt%28+%28-4%29%5E2-4%283%29%28-5%29+%29%29%2F%282%283%29%29 Negate -4 to get 4.


x+=+%284+%2B-+sqrt%28+16-4%283%29%28-5%29+%29%29%2F%282%283%29%29 Square -4 to get 16.


x+=+%284+%2B-+sqrt%28+16--60+%29%29%2F%282%283%29%29 Multiply 4%283%29%28-5%29 to get -60


x+=+%284+%2B-+sqrt%28+16%2B60+%29%29%2F%282%283%29%29 Rewrite sqrt%2816--60%29 as sqrt%2816%2B60%29


x+=+%284+%2B-+sqrt%28+76+%29%29%2F%282%283%29%29 Add 16 to 60 to get 76


x+=+%284+%2B-+sqrt%28+76+%29%29%2F%286%29 Multiply 2 and 3 to get 6.


x+=+%284+%2B-+2%2Asqrt%2819%29%29%2F%286%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%284%2B2%2Asqrt%2819%29%29%2F%286%29 or x+=+%284-2%2Asqrt%2819%29%29%2F%286%29 Break up the expression.


x+=+%282%2Bsqrt%2819%29%29%2F%283%29 or x+=+%282-sqrt%2819%29%29%2F%283%29 Reduce


So our answers are x+=+%282%2Bsqrt%2819%29%29%2F%283%29 or x+=+%282-sqrt%2819%29%29%2F%283%29


which approximate to x=2.12 or x=-0.786