What is x if x + 2y = 10 and y = 3?
Choose the correct answer
A) 1 B) 2 C) 3 D) 4 E) 5

Rationale: "substitute y by 3 in x + 2 y = 10 x + 2 ( 3 ) = 10 x + 6 = 10 if we substitute x by 4 in x + 6 = 10 , we have 4 + 6 = 10 . hence x = 4 correct answer d"
Answer: D