Question

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

correct ordered pair.
5x - 2y = 9
3x + 4y = -5
A. (5,5)
B. (3,3)
c. (1,-2)
D. (7.13)

Answer 1

x=1, y=-2. (1, -2).

Explanation:

5x-2y=9

3x+4y=-5

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

2(5x-2y)=2(9)

3x+4y=-5

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

10x-4y=18

3x+4y=-5

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

13x=13

x=13/13

x=1

5(1)-2y=9

5-2y=9

2y=5-9

2y=-4

y=-4/2

y=-2

Answer 2

Option C

The correct ordered pair is (1, -2)

Solution:

Given system of equations are:

5x - 2y = 9 ---- eqn 1

3x + 4y = -5 ----- eqn 2

We have to use elimination method to solve the system of equations

Multiply eqn 1 by 2

10x - 4y = 18 ---- eqn 3

Add eqn 2 and eqn 3

3x + 4y = -5

10x - 4y = 18

(+) -------------------

13x = 13

x = 1

Substitute x = 1 in eqn 1

5x - 2y = 9

5(1) - 2y = 9

5 - 2y = 9

2y = -4

y = -2

Thus the ordered pair (1, -2) Option C is correct