SOLUTION: Solve using the quadratic formula. 2x2 - 5x – 10 = 0

Algebra ->  Divisibility and Prime Numbers -> SOLUTION: Solve using the quadratic formula. 2x2 - 5x – 10 = 0       Log On


   

Question 84110: Solve using the quadratic formula.
2x2 - 5x – 10 = 0

Found 2 solutions by jim_thompson5910, venugopalramana:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 2x%5E2%2B-5x%2B-10+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-5%29%5E2-4%2A2%2A-10=105.

Discriminant d=105 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--5%2B-sqrt%28+105+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-5%29%2Bsqrt%28+105+%29%29%2F2%5C2+=+3.8117376914899
x%5B2%5D+=+%28-%28-5%29-sqrt%28+105+%29%29%2F2%5C2+=+-1.3117376914899

Quadratic expression 2x%5E2%2B-5x%2B-10 can be factored:
2x%5E2%2B-5x%2B-10+=+2%28x-3.8117376914899%29%2A%28x--1.3117376914899%29
Again, the answer is: 3.8117376914899, -1.3117376914899. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B-5%2Ax%2B-10+%29

Answer by venugopalramana(3286) About Me  (Show Source):
You can put this solution on YOUR website!
Solve using the quadratic formula.
2X^2-5X-10=0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%285+%2B-+sqrt%28+5%5E2-4%2A2%2A%28-10%29+%29%29%2F%282%2A2%29+
x+=+%285+%2B-+sqrt%28+25%2B80+%29%29%2F%284%29+
x+=+%285+%2B-+sqrt%28+105+%29%29%2F%284%29+