Question

Cramer's rule:
What is [Ax] in the system below?

Answer 1

C

Explanation:

Edge2021

Answer 2

Ax =
`\left[\begin{array}{cc}-3&-1\\5&1\end{array}\right]` ⇒ 3rd answer

Explanation:

Lets revise the Cramer's rule

- If the system of equation is ax + by = c and dx + ey = f

- A is the matrix represent this system of equation

- The first column has the coefficients of x, and

the second column has the coefficients of y

∴ A =
`\left[\begin{array}{cc}a&b\\d&e\end{array}\right]`

- Ax means replace the column of x by the answers of the equation

∴ Ax =
`\left[\begin{array}{cc}c&b\\f&e\end{array}\right]`

- Ay means replace the column of y by the answers of the equation

∴ Ay =
`\left[\begin{array}{cc}a&c\\d&f\end{array}\right]`

* Now lets solve the problem

∵ 4x - y = -3 and -2x + y = 5

∴ A =
`\left[\begin{array}{cc}4&-1\\-2&1\end{array}\right]`

- Replace the column of x by the answer to get Ax

∴ Ax =
`\left[\begin{array}{cc}-3&-1\\5&1\end{array}\right]`

* Ax in the system of equation is
`\left[\begin{array}{cc}-3&-1\\5&1\end{array}\right]`