eq1: (2 * x) + (3 * y) = 5
a = 6 (slider from -10 to 10, step 0.5)
eq2: (4 * x) + (a * y) = 6
eq3: (2 * x) + (3 * y) = 5
b = 1 (slider from -5 to 5)
eq4: (4 * x) + (6 * y) = b
c = 2 (slider from -5 to 5)
eq5: x - (c * y) = c
eq6: (2 * x) - (4 * y) = (2 * c)