20 = -d + 6<br><br>A. -17<br>B. 7<br>C. 14<br>D. -14

<span>Look at the definition of multiplicative inverse. If two numbers are multiplicative inverses of each other, then by definition, their product will be equal to 1. And 1 is a positive number. If both numbers being multiplied are positive, then the result is positive. And of both numbers being multiplied are negative, then the result is still positive. But if one number is positive and the other is negative, then the result is negative. So if you want a positive result, then both numbers you're multiplying have to have the same sign. And since we want a result of 1 for multiplicative inverses and since 1 is positive, then the numbers being multiplied have to have the same sign.</span>

7 0

3 years ago

What is the row echelon form of this matrix?

USPshnik [31]

The row echelon form of the matrix is presented as follows;

$\begin{bmatrix}1 &-2 &-5 \\ 0& 1 & -7\\ 0&0 &1 \\\end{bmatrix}$

<h3>What is the row echelon form of a matrix?</h3>

The row echelon form of a matrix has the rows consisting entirely of zeros at the bottom, and the first entry of a row that is not entirely zero is a one.

The given matrix is presented as follows;

$\begin{bmatrix}-3 &6 &15 \\ 2& -6 & 4\\ 1&0 &-1 \\\end{bmatrix}$

The conditions of a matrix in the row echelon form are as follows;

There are row having nonzero entries above the zero rows.
The first nonzero entry in a nonzero row is a one.
The location of the leading one in a nonzero row is to the left of the leading one in the next lower rows.

Dividing Row 1 by -3 gives:

$\begin{bmatrix}1 &-2 &-5 \\ 2& -6 & 4\\ 1&0 &-1 \\\end{bmatrix}$