Answer: A
Hope this is helpful.
Explanation:
Try to solve using simultaneous equations with each answer given.
x + 2y = 5
x = 5 - 2y
Plug this into each equation
A 2(5 - 2y) + 4y = 3
10 - 4y + 4y = 3
10 = 3 in consistent
B 5(5 - 2y) + 2y = 3
25 - 10 y + 2y = 3
25 - 8y = 3
8y = 22
y = 2.75
Using original equation solve for x
5x + 2(2.75) = 3
5x + 5.5 = 3
5x = -2.5
x = -0.5
Using original equation,
(-0.5) + 2 (2.75) = 5
-0.5 + 5.5 = 5 consistent
C 6x + 12y = 30
6(5 - 2y) + 12y = 30
30 - 12y + 12 y = 30 consistent for every value of y
D 3(5 - 2y) + 4y = 8
15 - 6y + 4y = 8
- 2y = -7
y = 3.5
x = 5 - 2y
x = 5 - 7
x = -2
Solving for x
3(-2) + 4(3.5) = -6 + 14 = 8 consistent
So A is the correct answer