Question

Use the substitution method to solve the system of equations. Choose the correct ordered pair. x + y = 11 -x = -y - 9

a. (9, 2)
b. (10, 1)
c. (8, 3)
d. (11, 0)

Answer 1

B

Explanation:

Apex

Answer 2

`x+y=11 \\ -x=-y-9 \\ \\ \hbox{substitute the second equation by -1} \\ \\ x+y=11 \\ x=y+9 \\ \\ \hbox{substitute y+9 for x in the first equation} \\ \\ y+9+y=11 \\ 2y=11-9 \\ 2y=2 \\ y=(2)/(2) \\ y=1 \\ \\ x=y+9 \\ x=1+9 \\ x=10 \\ \\ (x,y)=(10,1)`

The answer is B.