SOLUTION: solve the following equation. express roots to the nearest hundredth. 2m^2-m-7=0

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Question 7318: solve the following equation. express roots to the nearest hundredth.
2m^2-m-7=0
Found 2 solutions by ichudov, glabow:
Answer by ichudov(507) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation am%5E2%2Bbm%2Bc=0 (in our case 2m%5E2%2B-1m%2B-7+=+0) has the following solutons:

m%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=%28-1%29%5E2-4%2A2%2A-7=57.

Discriminant d=57 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--1%2B-sqrt%28+57+%29%29%2F2%5Ca.

m%5B1%5D+=+%28-%28-1%29%2Bsqrt%28+57+%29%29%2F2%5C2+=+2.13745860881769
m%5B2%5D+=+%28-%28-1%29-sqrt%28+57+%29%29%2F2%5C2+=+-1.63745860881769

Quadratic expression 2m%5E2%2B-1m%2B-7 can be factored:
2m%5E2%2B-1m%2B-7+=+2%28m-2.13745860881769%29%2A%28m--1.63745860881769%29
Again, the answer is: 2.13745860881769, -1.63745860881769. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B-1%2Ax%2B-7+%29

Answer by glabow(165) About Me  (Show Source):
You can put this solution on YOUR website!
The quadratic equation is your friend here.
a = 2
b = -1
c = -7
Go to it!
%28-b+%2B-+sqrt%28b%5E2+-+4ac%29%29%2F2a
At the start, I get
%281+%2B-+sqrt%281+%2B+56%29%29%2F4
Can you finish it? [do the work to get 2.14 and -1.64, or thereabouts]