If x = 3 and 3 = y, then x = y
This is an example of the transitive property of algebra. Transitive property is one of the properties of equality.
Other properties of equality in algebra are:
1) multiplicative property of zero: a * 0 = 0 = 0 * a
2) zero product : if ab = 0 ; then a = 0 or b = 0
3) reflexive : a = a
4) symmetric : if a = b, then b = a
5) addition : if a = b , then a + c = b + c
6) subtraction : if a = b , then a - c = b - c
7) multiplication: if a = b , then ac = bc
8) division: if a = b and c not = 0, then a / c = b / c
9) Substitution : if a = b, then b can substitute for a in any equation.