SOLUTION: 9x^2+11x+18=-10x+8

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: 9x^2+11x+18=-10x+8      Log On


   

Question 499743: 9x^2+11x+18=-10x+8
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

9x%5E2%2B11x%2B18=-10x%2B8 Start with the given equation.


9x%5E2%2B11x%2B18%2B10x-8=0 Get every term to the left side.


9x%5E2%2B21x%2B10=0 Combine like terms.


Notice that the quadratic 9x%5E2%2B21x%2B10 is in the form of Ax%5E2%2BBx%2BC where A=9, B=21, and C=10


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-%2821%29+%2B-+sqrt%28+%2821%29%5E2-4%289%29%2810%29+%29%29%2F%282%289%29%29 Plug in A=9, B=21, and C=10


x+=+%28-21+%2B-+sqrt%28+441-4%289%29%2810%29+%29%29%2F%282%289%29%29 Square 21 to get 441.


x+=+%28-21+%2B-+sqrt%28+441-360+%29%29%2F%282%289%29%29 Multiply 4%289%29%2810%29 to get 360


x+=+%28-21+%2B-+sqrt%28+81+%29%29%2F%282%289%29%29 Subtract 360 from 441 to get 81


x+=+%28-21+%2B-+sqrt%28+81+%29%29%2F%2818%29 Multiply 2 and 9 to get 18.


x+=+%28-21+%2B-+9%29%2F%2818%29 Take the square root of 81 to get 9.


x+=+%28-21+%2B+9%29%2F%2818%29 or x+=+%28-21+-+9%29%2F%2818%29 Break up the expression.


x+=+%28-12%29%2F%2818%29 or x+=++%28-30%29%2F%2818%29 Combine like terms.


x+=+-2%2F3 or x+=+-5%2F3 Simplify.


So the solutions are x+=+-2%2F3 or x+=+-5%2F3