SOLUTION: Use the quadratic formula to find the roots of the equation. Round to tenths if necessary. 3x2 - 4x - 8 = 0

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Question 244515: Use the quadratic formula to find the roots of the equation. Round to tenths if necessary. 3x2 - 4x - 8 = 0
Answer by solver91311(24713) 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 3x%5E2%2B-4x%2B-8+=+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=%28-4%29%5E2-4%2A3%2A-8=112.

Discriminant d=112 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--4%2B-sqrt%28+112+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-4%29%2Bsqrt%28+112+%29%29%2F2%5C3+=+2.43050087404306
x%5B2%5D+=+%28-%28-4%29-sqrt%28+112+%29%29%2F2%5C3+=+-1.09716754070973

Quadratic expression 3x%5E2%2B-4x%2B-8 can be factored:
3x%5E2%2B-4x%2B-8+=+3%28x-2.43050087404306%29%2A%28x--1.09716754070973%29
Again, the answer is: 2.43050087404306, -1.09716754070973. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+3%2Ax%5E2%2B-4%2Ax%2B-8+%29



Remember to round to the nearest tenth per the instructions.


John