What’s the awnser to this please

Answer:
BC=6
Step-by-step explanation:
The perimeter is the sum of all the side lengths.
Thus, add up all the sides.
And we already know the perimeter is 64. Thus:
[tex](3z)+(10)+(z-1)+(2z+3)+(10)=64[/tex]
Combine like terms and add the numbers:
[tex]6z+22=64[/tex]
Subtract 22 from both sides:
[tex]6z=42[/tex]
Divide by 6:
[tex]z=7[/tex]
So, z is 7.
BC is z-1. Therefore:
[tex]BC=z-1\\BC=7-1=6[/tex]
So, BC is 6.