Solve for (x, y) in the equation 2x + y = 4: x^2 + xy = 12

A.
(6, 8): (2, 8) 
B.
(3, 4): (1, 4) 
C.
(8, 4): (1, 4) 
D.
(8, 6): (8, 2) 
E.
(4, 3): (4, 1)
Correct Answer: Option A
Explanation
2x + y = 4……(i)
x^2 + xy = 12……..(ii)
from eqn (i), y = 4 – 2x
= x2 + x(4 – 2x)
= 12
x2 + 4x – 2×2 = 12
4x – x2 = 12
x2 – 4x – 12 = 0
(x – 6)(x + 2) = 0
sub. for x = 6, in eqn (i) y = 8, 8
=(6,8); (2, 8)