Select all the relations which represent a function. A. (1,3), (2,5), (2,7), (4,9)
B. (1,3), (2,5), (3,7), (4,9)
C. (1,3), (1,5), (1,7), (4,9)
D. (1,3), (2,3), (3,3), (4,3)
E. (1,2), (2,5), (2,1), (4,5)

please help

(B), (D)

Step-by-step explanation:

A. (1,3), (2,5), (2,7), (4,9) NOT a function

B. (1,3), (2,5), (3,7), (4,9) - YES, it's a function

C. (1,3), (1,5), (1,7), (4,9) NOT a function

D. (1,3), (2,3), (3,3), (4,3) - YES, it's a function

E. (1,2), (2,5), (2,1), (4,5) NOT a function

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