Question

Use matrix method to solve 2+y=3,x+2y=9

Answer 1

x= -1, y= 5

Explanation:

Please see the attached picture for the full solution.

Matrix A is called the coefficient matrix. This means that its elements are the coefficient of x and y. In matrix X, write the unknown variables. Then write the constants in matrix B.

Theorem:

`{A}^( - 1) A = I`

☆ I is an identity matrix and can be treated as 1 when multiplying.

`{A}^( - 1) = (1)/( |A| ) adj(A)`

☆
`|A|` is the determinant of A

☆ adj(A) is the adjoint of matrix A