5/12x+3/4=5/6
5/12x = 5/6 - 3/4
5x = 12 *( 5 * 2 - 3 * 3) / 12
x = 1 / 5
4.72-2.5x=2x+2.92
-2.5x - 2x = 2.92 - 4.72
-4.5x = -1.8
x = (18 / 10) / (45 / 10)
x = 18 /45
x = 2 / 5 = 0.4
5/8y-3/4=2y-12/5
5/8y - 2y = -12/5 + 3/4
-11/8y = (-4 * 12 + 15) / 20
-11/8y = -33/20
y = (33 * 8) /(20 * 11)
y = 6 / 5 = 1.2
4(1-0.5a)= -2(3+2a)
-2(1 - 0.5a) = 3+ 2a
-2 + a = 3 + 2a
-a = 5
a = -5