SOLUTION: Solve using the quadratic formula: z^2 - 3z = 40

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Question 157134: Solve using the quadratic formula: z^2 - 3z = 40
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
Solve using the quadratic formula: z^2 - 3z = 40
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z^2 - 3z - 40 = 0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
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=169 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 8, -5. Here's your graph:

The onsite solver always uses x. Just sub z for x.
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