Find the missing number ____:7 = 12:21 A) 3 B) 14 C) 4 D) 12
2 answers:
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Answer:
Step-by-step explanation:
Correct Answer: C
We can rely on the guess and check method to easily solve this problem. Let’s first pick arbitrary values of x and y to eliminate some answer choices.
Let’s consider the case where |x| and let x = 3 and y = -10.
Because x/y = -3/10 < 1, answer choice A is incorrect.
Because |x|2 = (3)2 = 9 and |-10| = 10, we have that |x|2 < y, so answer choice B is also incorrect.
Because x2 + 1= (3)2 + 1 = 10 and y2 + 1 = (10)2 + 1 = 101, we have that x2 + 1 < y2 + 1, so answer choice D is also incorrect.
Now, let’s consider the case where |x|>|y| and let x = 3 and y = -2.
Then, x-2 = 1/x2 = 1/9 and y-2 = 1/y2 = 1/4. This means that x-2 < y-2 , so answer choice E is also incorrect.
This means that answer choice C is correct. We can manipulate the inequality to see why this is true: (x/3 – 5) > (y/3 – 5)
We add 5 to both sides: x/3 > y/3
We multiply both sides by 3: x > y.
We know this is true since we are given that x > 1 > -1 > y, which simplifies to x > y.
