The x is horizontal on a graph and then the y axis is vertical on a graph.
Z=1 eventually you get 15 divided by 15 giving you Z=1 it’s a long equation
X=12 because 12 times 12 equals 144 or 12 to the power of two equals 144
2(21x − 7) + 4(3x + 2) = 6(2x + 9) + 3
42x - 14 + 12x + 8= 12x + 54 + 3
54x - 6= 12x + 57
54x=12x + 63
42x=63
x= 63/42
x= 3/2