# Equations

Given 2 equations on the variables x and y, solve for x and y. Input The first line of input contains N, the number of test cases. Each test case consists of two equations, each on a separate line. An empty line separates cases. An equation consists of two or more terms separated by addition, subtraction, or equality operators. A term is an integer, or a variable name (x or y) optionally pre- ceded by a minus sign or an integer coefficient. There is exactly one equality operator. All operators are sur- rounded by spaces, and there are no spaces within terms. Output For each case, print two lines, giving the values of x and y as rationals in simplest terms. If x or y has no unique rational value such that both equations hold, print ‘don't know’ for its value. Print an empty line between cases. Sample Input 7 2x + 3y = x 5=x+y+3 2x + 3y = 0 10x = -15y 2x + 3y = 0 10x = -15y + 1 x=1 3x = 6y 2x = 3x + -x + y x+y=x+y 2x = -3 -2y = 3 1=2 x=3 Sample Output 3

2/2 -1 don't know don't know don't know don't know 1 1/2 don't know 0 -3/2 -3/2 don't know don't know