Roland2rule wrote:If X = -|Y| and X-Y =-10, what is Y?
A. -5 or +5
B. -10
C. 0
D. -5
E. 5
QA is e.
I have been struggling since on how to get Y=-5.
From x = -|y|, we know that |y| is positive, thus, x is a negative number. Also, the absolute values of x and y are equal. For example, if x = -2, then y is either +2 or -2.
Given, x - y = -10
=> -|x| - y = -10; we already deduced that x is negative.
=> |x| + y = 10; multiplying the equation by '-'.
Case 1: Say x = -a, and y = +a
Thus, |-a| + a = 10 => a + a = 10 => a = 5 => y = 5.
Case 2: Say x = -a, and y = -a
Thus, |-a| - a = 10 => a - a = 10. This is not possible, thus y must be positive.
Thus, y = 5.
The correct answer:
E
Hope this helps!
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