Question

Find 'a'.
Solve using substitution or elimination method.

Answer 1

\[\left(\begin{matrix}a \\ 10\end{matrix}\right)+\left(\begin{matrix}a \\ -5\end{matrix}\right)=\left(\begin{matrix}8 \\ 5\end{matrix}\right)\]

Answer 2

4

Answer 3

Can u explain me how? @AndreyZn

Answer 4

of course, I can. It's the matrix's property of sum. we sum a+a and write in the first line, then sum 10 and (-5) = 5 and write it in the second line. So the result is the new matrix with two lines: first 8 and second 5. 5 is the result of 10-5 and 8 is result of a+a. so, a+a=8, that is 2a=8, so a=4

Answer 5

\(\large \begin{bmatrix}
a\\
10
\end{bmatrix}+
\begin{bmatrix}
a\\-5
\end{bmatrix}=
\begin{bmatrix}
a+a\\ 10+(-5)
\end{bmatrix}\implies
\begin{bmatrix}
8\\5
\end{bmatrix}\)

Answer 6

see what "a" is?

Answer 7

OK OK thnkyou @AndreyZn