<p>I encounter this question on yahoo answers:</p>
<p>let the function g be defined by g(x) = 2x -3. If g(k) = g(2k-3), what is the value of g(4k)?</p>
<p>I got 21 as an answer but other people got different answers. What do you think? Is 21 your answer too!</p>
<p>Have a nice day</p>
<p>g(k) = 2k-3 and g(2k-3) =2(2k-3)-3=4k-6-3=4k-9. So 2k-3=4k-9. So 6=2k and k=3.</p>
<p>Now, g(4k)=g(4*3)=g(12) = 2(12)-3=24-3=21.</p>
<p>So 21 is correct.</p>
<p>A tiny time saver: when g(x) is monotonic, it follows from g(x1)=g(x2) that x1=x2.</p>
<p>g(k) = g(2k-3)
k = 2k - 3
k = 3
…</p>