Question

2x - y = 5

x + 3y = 7
What is the value of the y-determinant?
7
9
22

Answer 1

Your answer would be 9

Answer 2

9 is the correct answer.

Explanation:

The general form of the determinant of the given system

ax + by = e

cx + dy = f

is
`\begin{vmatrix}a & b\\ c & d\end{vmatrix}`

Now, we have the given system, i.e.

2x - y = 5

x + 3y = 7

The y-determinant of a system is formed by taking the constant terms and placing them in the y‐coefficient positions in the general determinant form and keeping the x-coefficients same.

So, we get,

`\begin{vmatrix}2 & 5\\ 1 & 7\end{vmatrix}`

Solve the above determinant i.e. 2*7 - 1*5 = 14 - 5 = 9

Hence, the value of y-determinant is 9.