Question

Pls explain this, I don't understand​

Answer 1

AB =
`\left[\begin{array}{ccc}0&-2\\4&-12\\\end{array}\right]`

Explanation:

To obtain the first row of AB

Sum the products of corresponding elements in row 1 of A with elements in column 1 and 2 of B

To obtain the second row of AB

Sum the corresponding elements in row 2 of A with elements in column 1 and 2 of B, that is

AB =
`\left[\begin{array}{ccc}0(-1)+2(0)&0(3)+2(-1)\\-4(-1)+0(0)&-4(3)+0(-1)\\\end{array}\right]`

=
`\left[\begin{array}{ccc}0+0&0-2\\4+0&-12+0\\\end{array}\right]`

=
`\left[\begin{array}{ccc}0&-2\\4&-12\\\end{array}\right]`