If x + y = 2y – x + 1 = 5, find the value of x
-
A.
3 -
B.
2 -
C.
1 -
D.
-1
Correct Answer: Option B
Explanation
x + y = 2y – x + 1 = 5
x + y = 2y – x + 1
x + x + y – 2y = 1
2x – y = 1….(i)
2y – x + 1 = 5
-x + 2y = 5 + 1
-x = 2y = 4
x – 2y = -4 …..(ii)
solve simultaneously (i) x 2x – y = 1
(ii) x x – 2y = -4
2x – y = 1
=2x – 4y = -8
3y = 9
y = (frac{9}{3})
y = 3
substitute y = 3 into equation (i)
2x – y = 1
2x – 3 = 1
2x = 1 + 3
2x = 4
x = (frac{4}{2})
= 2