SOLUTION: 7x^2-3x-3=0

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: 7x^2-3x-3=0      Log On


   

Question 315573: 7x^2-3x-3=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

7x%5E2-3x-3=0 Start with the given equation.


Notice that the quadratic 7x%5E2-3x-3 is in the form of Ax%5E2%2BBx%2BC where A=7, B=-3, and C=-3


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-%28-3%29+%2B-+sqrt%28+%28-3%29%5E2-4%287%29%28-3%29+%29%29%2F%282%287%29%29 Plug in A=7, B=-3, and C=-3


x+=+%283+%2B-+sqrt%28+%28-3%29%5E2-4%287%29%28-3%29+%29%29%2F%282%287%29%29 Negate -3 to get 3.


x+=+%283+%2B-+sqrt%28+9-4%287%29%28-3%29+%29%29%2F%282%287%29%29 Square -3 to get 9.


x+=+%283+%2B-+sqrt%28+9--84+%29%29%2F%282%287%29%29 Multiply 4%287%29%28-3%29 to get -84


x+=+%283+%2B-+sqrt%28+9%2B84+%29%29%2F%282%287%29%29 Rewrite sqrt%289--84%29 as sqrt%289%2B84%29


x+=+%283+%2B-+sqrt%28+93+%29%29%2F%282%287%29%29 Add 9 to 84 to get 93


x+=+%283+%2B-+sqrt%28+93+%29%29%2F%2814%29 Multiply 2 and 7 to get 14.


x+=+%283%2Bsqrt%2893%29%29%2F%2814%29 or x+=+%283-sqrt%2893%29%29%2F%2814%29 Break up the expression.


So the solutions are x+=+%283%2Bsqrt%2893%29%29%2F%2814%29 or x+=+%283-sqrt%2893%29%29%2F%2814%29