What is this matrix called
[2,5,6]

The dimension of a matrix is indicated with R × C where R is the number of rows in the matrix and C is the number of columns. When a matrix has the same number of rows as columns, then it's a square matrix. Matrices with just one row are called row matrices, and those with only one column are column matrices.

if you use photomath right away it will give you the answer not like this app that you have to wait for people.