EXPLANATION
The perimeter Perimeter is given by the sum of the sides as follows:
P = z + 5 + z + 5 + z + z
Substituting P=26 and adding like terms,
26 = 10 + 4z
Subtracting -10 to both sides:
26 - 10 = 10 - 10 + 4z
Simplifying:
16 = 4z
Dividing both sides by 4:
16/4 = z
Switching and simplifying:
z = 4
So,
Equation: 26 = 10 + 4z
z = 4