week 7 precalc 11 – Noah's Blog

This week in Precalc 11 we finished unit 3 with the quadratic equation and interpreting the discriminant.

In lesson 3.4 we learned how to use the quadratic formula : $x=-b \mp \frac{\sqrt{b^2-4ac}}{2a}$ to solve quadratic equations. i found this especially useful with fractions and decimals.

Ex :

$x=2x^2-6x+1=0$

$x=\frac{6 \mp \sqrt{6^2-4(2)(1)}}{4}$

$x=\frac{6 \mp \sqrt {28}}{4}$

$x=\frac{3 \mp \sqrt{7}}{2}$

In lesson 3.5 we learned how to interpret the discriminant : $b^2-4ac$ and how to find whether they are equal roots, real roots, no real roots etc. We also learned how to find the value of a variable when the equation has no real roots, one real root etc.