# Precalculus Examples

The inverse of a matrix can be found using the formula where is the determinant of .

If then

These are both valid notations for the determinant of a matrix.

The determinant of a matrix can be found using the formula .

Simplify the determinant.

Simplify each term.

Multiply by to get .

Multiply by to get .

Subtract from to get .

Substitute the known values into the formula for the inverse of a matrix.

Simplify element by multiplying to get .

Simplify element by multiplying to get .

Multiply by each element of the matrix.

Simplify element by multiplying to get .

Simplify element by multiplying to get .

Simplify element by multiplying to get .

Simplify element by multiplying to get .