SOLUTION: solve by applying the quadratic formula; all radicals should be simplified as far as possible. show your work. {{{9x^2+4x-5=0}}} I could use some help with this problem ple

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: solve by applying the quadratic formula; all radicals should be simplified as far as possible. show your work. {{{9x^2+4x-5=0}}} I could use some help with this problem ple      Log On


   

Question 335940: solve by applying the quadratic formula; all radicals should be simplified as far as possible. show your work.

9x%5E2%2B4x-5=0
I could use some help with this problem please.

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

9x%5E2%2B4x-5=0 Start with the given equation.


Notice that the quadratic 9x%5E2%2B4x-5 is in the form of Ax%5E2%2BBx%2BC where A=9, B=4, and C=-5


Let's use the quadratic formula to solve for "x":


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


x+=+%28-%284%29+%2B-+sqrt%28+%284%29%5E2-4%289%29%28-5%29+%29%29%2F%282%289%29%29 Plug in A=9, B=4, and C=-5


x+=+%28-4+%2B-+sqrt%28+16-4%289%29%28-5%29+%29%29%2F%282%289%29%29 Square 4 to get 16.


x+=+%28-4+%2B-+sqrt%28+16--180+%29%29%2F%282%289%29%29 Multiply 4%289%29%28-5%29 to get -180


x+=+%28-4+%2B-+sqrt%28+16%2B180+%29%29%2F%282%289%29%29 Rewrite sqrt%2816--180%29 as sqrt%2816%2B180%29


x+=+%28-4+%2B-+sqrt%28+196+%29%29%2F%282%289%29%29 Add 16 to 180 to get 196


x+=+%28-4+%2B-+sqrt%28+196+%29%29%2F%2818%29 Multiply 2 and 9 to get 18.


x+=+%28-4+%2B-+14%29%2F%2818%29 Take the square root of 196 to get 14.


x+=+%28-4+%2B+14%29%2F%2818%29 or x+=+%28-4+-+14%29%2F%2818%29 Break up the expression.


x+=+%2810%29%2F%2818%29 or x+=++%28-18%29%2F%2818%29 Combine like terms.


x+=+5%2F9 or x+=+-1 Simplify.


So the solutions are x+=+5%2F9 or x+=+-1

If you need more help, email me at jim_thompson5910@hotmail.com

Also, feel free to check out my website.

Jim