x_1 +

x_2 =

a_1 = 1 (slider from -5 to 5, step 0.5)
a_2 = -0.5 (slider from -5 to 5, step 0.5)
c = -1 (slider from -5 to 5, step 0.5)
gl1: (a_1 * x) + (a_2 * y) = c