Official Solution:If \(a\) and \(b\) are integers such that \(a < b < 0\) and \(a^2 = b^2 + 7\), what is the value of \(a-b\)?A. -7
B. -4
C. -3
D. -1
E. 1
Given: \(a^2=b^2+7\).
Rearrange and apply \(a^2 - b^2 = (a - b)(a + b)\) to get \((a - b)(a + b) = 7\). Since \(a\) and \(b\) are integers, both \(a + b\) and \(a - b\) are integers as well. Thus, we have the product of two integers equal to 7. There are only two combinations of such factors possible: (1, 7) and (-1, -7). Given that both \(a\) and \(b\) are negative, the first case is not possible, so \(a - b\) must be either -1 or -7. However, it cannot be -7 because in this case, \(a + b\) must be -1, and no two negative integers yield a sum of -1. Therefore, \(a - b = -1\).
Answer: D