Carcass wrote:
If y >2, and \(\frac{(x−2)^2+6}{y}\) = \(\frac{70y+70}{y+y^2}\) which of the following could be the value of 2x + 3?
A) -9
B) -6
C) 0
D) 10
E) 17
Given: \(\frac{(x−2)^2+6}{y}=\frac{70y+70}{y+y^2}\)
Factor the right side: \(\frac{(x−2)^2+6}{y}=\frac{70(y+1)}{y(1+y)}\)
Since \(y > 2\), we know that \(y + 1 \neq 0\), which means we can safely divide numerator and denominator by \(y + 1\) to get: \(\frac{(x−2)^2+6}{y}=\frac{70}{y}\)
Since both sides of the equation have the same nonzero denominator (\(y\)), we can conclude that: \((x−2)^2+6 = 70\)
Expand and simplify the left side: \(x^2-4x+10 = 70\)
Set the equation equal to \(0\) to get: \(x^2-4x-60 = 0\)
Factor: \((x-10)(x+6) = 0\)
So, either \(x = 10\) or \(x = -6\)
If \(x = 10\), then \(2x + 3 = 2(10) + 3 = 20 + 3 = 23\)
\(23\) is not among the other choices, so we'll try the other possible x-value
If \(x = -6\), then \(2x + 3 = 2(-6) + 3 = (-12) + 3 = -9\)
Answer: A