MathDB
The Number of Lines

Source: 1999 National High School Mathematics League, Exam One, Problem 11

March 10, 2020

Problem Statement

Line l:ax+by+c=0l:ax+by+c=0, where a,b,c∈{−3,−2,−1,0,1,2,3}a,b,c\in\{-3,-2,-1,0,1,2,3\}, and a,b,ca,b,c are different. If the bank angle of ll is an acute angle, then the number of such lines is________.
Back to ProblemsView on AoPS