SOLUTION: solve 2r^2 + 3r-1=0 answer: -3 + sqrt 17/4, -3-sqrt 17/4 need a full break down of how my text book got this answer

Question 193384: solve 2r^2 + 3r-1=0

answer: -3 + sqrt 17/4, -3-sqrt 17/4
need a full break down of how my text book got this answer
Answer by yuendatlo(23) (Show Source): You can put this solution on YOUR website!

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=17 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 0.280776406404415, -1.78077640640442. Here's your graph:

sorry about the weird decimals
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