The coordinates of a point are (4, –1). which matrix expression represents translating the point 3 units to the left and 7 units up?

The point (4, -1) is represented as:

| 4 |
|    |
|-1 |

Please, understand that the three vertical | represent a continuous line, which is the matrix representation.

The traslataion of 3 units to the left and 7 units up means that you have to add the matrix:

|- 3|
|    |
|7  |

So the representation is:

|4  |          |-3 |       |1  |
|    |    +    |    | =    |    |
|-1 |          |7  |       |6  |

when solving sales tax it's pretty simple because all you do is add everything for a subtotal and multiply your sub total by the tax so i'll use the first as an example your subtotal is 19.96 x0.05 to get 0.99 <-- your sales tax and your final total with tax to be 20.96