SOLUTION: Solve using the square root method or quadratic formula. 20x^2 - 31x-9 =0 I cant figure this one out because the numbers are so big, can you help me please?

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: Solve using the square root method or quadratic formula. 20x^2 - 31x-9 =0 I cant figure this one out because the numbers are so big, can you help me please?       Log On


   

Question 87519: Solve using the square root method or quadratic formula.
20x^2 - 31x-9 =0
I cant figure this one out because the numbers are so big, can you help me please?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for x:
20x%5E2-31x-9+=+0 Use the quadratic formula:x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a
Here, a = 20, b = -31, and c = -9
x+=+%28-%28-31%29%2B-sqrt%28%28-31%29%5E2-4%2820%29%28-9%29%29%29%2F2%2820%29
x+=+%2831%2B-sqrt%28961-%28-720%29%29%29%2F40
x+=+%2831%2B-sqrt%281681%29%29%2F40...andsqrt%281681%29+=+41 + or -, so...
x+=+%2831%2B41%29%2F40 or x+=+%2831-41%29%2F41
x+=+72%2F40 or x+=+-10%2F40
x+=+1.8 or x+=+-0.25