Week 10 – Discriminant

This week in Pre-Calculus 11 we reviewed for our midterm. So we are suppose to blog about something we haven’t blogged about yet. I chose the discriminant because it was something I struggled with until review this week. The discriminant is how we determine how many solutions there are. Here is how to find the discriminants b^2-4ac. This connects to the quadratic formula, the pink is the discriminant formula.

So you can have 2 solutions, 1 solution, or no solution.

x^2-6x+5=0

a=1, b=-6, c=5

b^2-4ac

Plug in a, b, and c.

(-6)^2-4(1)(5)

36-20

16 gives 2 solutions

This parabola crosses the x-axis twice giving us two solutions.

 

x^2-6x+9=0

a=1, b=-6, c=9

b^2-4ac

Plug in a, b, and c.

-6^2-4(1)(9)

36-36

0 gives one solution

The parabola crosses the x-axis once meaning there is only one solution.

 

x^2-6x+13=0

a=1, b=-6, c=13

b^2-4ac

Plug in a, b, and c.

-6^2-4(1)(13)

36-52

-16 gives no solution

The parabola never crosses the x-axis so there is no solution.

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