Question

Which systems of equations have the same solutions?

L (3x+y = 8
1x - 4y = -6
m{$*=*=230
NS 4x – 3y = 2
12% -8y = -12

Answer 1

B. L and N

Explanation:

Let's solve each system

✔️System L:

3x + y = 8 => Eqn. 1

x - 4y = -6 => Eqn. 2

x = -6 + 4y

Substitute x = (-6 + 4y) in eqn. 1

3(-6 + 4y) + y = 8

-18 + 12y + y = 8

-18 + 13y = 8

13y = 8 + 18

13y = 26

y = 26/13

y = 2

Substitute y = 2 into Eqn. 2

x - 4y = -6

x - 4(2) = -6

x - 8 = -6

x = -6 + 8

x = 2

Solution to system L = (2, 2)

✔️System M:

4x - 3y = 2 => Eqn. 1

5x - 4y = -30 => Eqn. 2

Multiply eqn 1 by 5, and eqn. 2 by 4

20x - 15y = 10

20x - 16y = -120

Subtract

y = 130

Substitute y = 130 into eqn. 1

4x - 3(130) = 2

4x - 390 = 2

4x = 2 + 390

4x = 392

x = 392/4 = 98

Solution to system M = (98, 130)

✔️System N:

4x - 3y = 2 =>Eqn. 1

2x - 8y = -12 => Eqn. 2

Multiply Eqn. 1 by 2, and eqn. 2 by 4

8x - 6y = 4

8x - 32y = -48

Subtract

26y = 52

y = 52/26

y = 2

Substitute y = 2 into eqn. 1

4x - 3(2) = 2

4x - 6 = 2

4x = 2 + 6

4x = 8

x = 8/4

x = 2

Solution to system N = (2, 2)