What is the determinant of b? a. −27 b. −30 c. 30 d. –6

Answer B:  -30

Step-by-step explanation:

Let B be as follows:

[-18 3]

[4    1 ]

To find the determinant, multiply diagonally downward from -18 through 1, obtaining -18.  We keep this sign as is.

Continue:  Start at 4 and move diagonally upward through 3; this product is 12. Because we moved upward, give this result the opposite sign:  -12.

Now add together these two products; that is, add together -18 and -12.  Here the sum is -30.  This is the determinant of the matrix.  It's Answer B.

Finding the determinant of a 3x3 matrix obviously requires more steps, but the general approach is similar.

u = -(6/7)w

step-by-step explanation:

place all values with 'u' on one side of the equation.

4u + 8w = - 3u + 2w

4u + 3u = 2w - 8w

further simplify the equation by solving the addition and subtraction.

7u = - 6w

make 'u' the independent variable by placing its co-efficient on the right-hand side.

u = - (6/7)w