Question

Use the elimination method to solve the system of equations. Choose the

correct ordered pair.
7x + 3y = 30
-2x + 3y= 3
A. (6,5)
B. (6,3)
C. (3,3)
D. (3,5)

Answer 1

(3,3)

Explanation:

7x + 3y = 30

-2x + 3y= 3

Multiply the second equation by -1 and add together to eliminate y

7x + 3y = 30

2x - 3y= -3

---------------------

9x + 0y = 27

Divide by 9

9x/9 = 27/9

x = 3

Now find y

-2x+3y = 3

-2(3) +3y =3

-6 +3y = 3

Add 6 to each side

3y = 3+6

3y=9

Divide by 3

y = 3

Answer 2

C

Explanation:

7x + 3y = 30 (equation 1)

-2x + 3y = 3 (equation 2)

9x = 27 (subtract the two equations to eliminate y)

x = 3 (divide by 9)

7 * 3 + 3y = 30 (Substitute x = 3 into equation 1, it doesn't matter which equation you substitute into)

21 + 3y = 30 (7 * 3 = 21)

3y = 9 (Subtract 21)

y = 3 (divide by 3)

Answer is (3, 3)