Question

Please help! Correct answer only, please! Determine the value of the following if it is possible. If it is not possible, explain. A. B. C. D.

Answer 1

Answer: C

Explanation:

Multiply the number outside of the matrix to EVERY value inside that matrix.

Addition and subtraction of matrices is very simple - just add (or subtract) the values of each matrix that have the same designation.

`X\left[\begin{array}{cc}a&b\\c&d\end{array}\right] +Y\left[\begin{array}{cc}e&f\\g&h\end{array}\right]=\left[\begin{array}{cc}X(a)+Y(e)&X(b)+Y(f)\\X(c)+Y(g)&X(d)+Y(h)\end{array}\right]\\\\\\\\\\-3\left[\begin{array}{cc}2&7\\8&-6\end{array}\right] +2\left[\begin{array}{cc}0&1\\4&-2\end{array}\right]\\\\\\=\left[\begin{array}{cc}-3(2)+2(0)&-3(7)+2(1)\\-3(8)+2(4)&-3(-6)+2(-2)\end{array}\right] \\\\\\=\left[\begin{array}{cc}-6&-19\\-16&14\end{array}\right]`