MathDB
1993 AMC 12 #4 - Special Operation

Source:

January 2, 2012
AMC

Problem Statement

Define the operation "∘\circ" by x∘y=4x−3y+xyx \circ y=4x-3y+xy, for all real numbers xx and yy. For how many real numbers yy does 3∘y=123 \circ y=12?
<spanclass=′latex−bold′>(A)</span> 0<spanclass=′latex−bold′>(B)</span> 1<spanclass=′latex−bold′>(C)</span> 3<spanclass=′latex−bold′>(D)</span> 4<spanclass=′latex−bold′>(E)</span> more than 4 <span class='latex-bold'>(A)</span>\ 0 \qquad<span class='latex-bold'>(B)</span>\ 1 \qquad<span class='latex-bold'>(C)</span>\ 3 \qquad<span class='latex-bold'>(D)</span>\ 4 \qquad<span class='latex-bold'>(E)</span>\ \text{more than}\ 4
Back to ProblemsView on AoPS