### 5.49.20 Multiply a row by an expression : mRow, scale, SCALE

mRow takes three arguments : an expression, a matrix A and an integer n.
mRow returns the matrix obtained by replacing in A, the row of index n by the product of the row of index n by the expression.
Input :

mRow(12,[[1,2],[3,4]],1)

Output :

[[1,2],[36,48]]

The scale (or SCALE) command is the same as mRow except that it takes the arguments in a different order; the matrix comes first, then the expression, then the integer.
Input:

scale([[1,2],[3,4]],12,1)

Output:

[[1,2],[36,48]]