## LaTex Array

Find the solution to the following system.
$\left \{ \begin{array}{cc} {y}={5}{x}+{25}\\{5}{x}-{4}{y}={-40} \end{array} \right.$

A. ${x}={5}, \;{y}={-4}$
B. ${x}={4}, \;{y}={5}$
C. ${x}={-5}, \;{y}={4}$
D. ${x}={-4}, \;{y}={5}$
E. ${x}={-4}, \;{y}={-5}$

## For-Commando

When there are $9$ points on the circle, how many triangles can be formed connecting three points?

A. $168$
B. $504$
C. $729$
D. $252$
E. $84$

## Talker

What is the area of below rectangle with base is 4 and height is 9?

A. 34
B. 33
C. 37
D. 36
E. 41

## plotter

Consider the following scatterplot of midterm and final exam scores for a class of 18 students.
Which of the following is incorrect?
A. The coefficient of determination here is positive.
B. Students who scored higher on the midterm exam tended to score higher on the final exam.
C. No one scored 90 or above on both exams.
D. The same number of students scored 100 on the midterm exam as scored 100 on the final exam.
E. The scatterplot shows a moderate negative correlation between midterm and final exam scores.

## transformer

Emily is experimenting with transformations by drawing the original triangle with a thin line, and the transformed triangle with a thick line.