1 REM  THIS PROGRAM SOLVES LINEAR EQUATIONS OF THE FORM
2 REM  A1*X1 + A2*X2 = B1, A3*X1 + A4*X3 = B2. THE DATA
3 REM  MUST FIRST LIST THE FOUR VALUES OF A IN ORDER, THEN
4 REM  THE DESIRED RIGHT HAND SIDES FOR WHICH SOLUTIONS
5 REM  ARE NEEDED.
10 READ A1, A2, A3, A4
15 LET D = A1 * A4 - A3 * A2
20 IF D = 0 THEN 65
30 READ B1, B2
37 LET X1 = (B1*A4 - B2 * A2 ) / D
42 LET X2 = ( A1 * B2 - A3 * B1)/D
55 PRINT X1, X2
60 GO TO 30
65 PRINT "NO UNIQUE SOLUTION"
70 DATA 1, 2,4
80 DATA 2, -7, 5
85 DATA 1, 3, 4, -7
90 END
