Here is the link to the playlist of videos that explain all of the math questions in the 2019 March SAT Question and Answer Service test. The playlists are separated by sections. Section 3 of the math section does not the allow use of calculator, whereas the calculator is permitted in Section 4 of the math section. The playlist will be accessible until the next official QAS is released.

## SAT math practice question: Simplifying complex number expressions

Try the following SAT math question (No Calculator, Grid in question) that tests your understanding of how to simplify complex number expressions.

When $\dfrac{9+7i}{3-i}$ is expressed in the form $a+bi$, what is the value of $a$ ? (Note $i = \sqrt{-1}$)

## 2018 PSAT Alternate Test: Video explanations

I just published my video playlist that explains all of the math questions in the 2018 PSAT Alternate test that was conducted on the 24th of October: **2018 PSAT Alternate Test Video Explanations**.

## 2018 PSAT Wednesday Test: Video explanations

Here is the link to the playlist of videos that explain all of the math questions in the 2018 PSAT Wednesday test that was conducted on the 10th of October: **2018 PSAT Wednesday Test Video Explanations**.

## SAT math practice question: Properties of parabolas

Try the following SAT math question (No Calculator) that tests your understanding of the graph of parabolas in the coordinate plane.

$$ y = (x-r)(x-s)$$

The equation above represents the graph of a parabola in the $xy-$plane, where $r$ and $s$ are constants, and $r \neq s$. Which of the following represents the $x-$coordinate of the vertex of the parabola?

- $\quad \dfrac{r-s}{2}$
- $\quad \dfrac{r+s}{2}$
- $\quad r-s$
- $\quad r+s$

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