RowAddMul
Returns a matrix with a multiple of one row added to another.
Syntax

RowAddMul(A, i, j, k)

A
is a matrix 
i
is a positive integer 
j
is a positive integer 
k
is a real number

Description
If A
is a matrix, i
and j
are valid row indices in A
, and k
is a real number, then RowAddMul(A, i, j, k)
returns A
with k
times its j
th row added to its i
th row.
This is an elementary row operation.
Examples
A ≔ ❨❨5, 1, 2, 3, 4❩, ❨4, 0, 2, 1, 7❩, ❨6, 3, 0, 4, 7❩, ❨4, 5, 2, 3, 9❩, ❨4, 0, 1, 2, 5❩❩
⎛5 1 2 3 4⎞ ⎜4 0 2 1 7⎟ ⎜6 3 0 4 7⎟ ⎜4 5 2 3 9⎟ ⎝4 0 1 2 5⎠
RowAddMul(A, 2, 5, −1)
⎛ 5 1 2 3 4⎞ ⎜ 0 0 1 −1 2⎟ ⎜ 6 3 0 4 7⎟ ⎜ 4 5 2 3 9⎟ ⎝ 4 0 1 2 5⎠