Please help! Please show all work! Thx!

Answer:
Part A)
[tex]86=2(x+22)[/tex]
Part B)
[tex]l=26\text{ cm}[/tex]
Step-by-step explanation:
We know that the rectangle has a length of (x+5) and a width of 12 cm.
Part A)
Remember the formula for the perimeter of a rectangle:
[tex]P=2(l+w)[/tex]
We know that the perimeter is 86. Substitute that for P:
[tex]86=2(l+w)[/tex]
Substitute (x+5) for the length l and 17 for w. So:
[tex]86=2((x+5)+17)[/tex]
We can simplify this to acquire our equation:
[tex]86=2(x+22)[/tex]
Part B)
To find the length, let's find our x first. We have the equation:
[tex]86=2(x+22)[/tex]
Divide both sides by 2:
[tex]43=x+22[/tex]
Now, subtract 22 from both sides. Therefore, our x is:
[tex]x=21[/tex]
To find the length, remember that the length is:
[tex]l=x+5[/tex]
Since we now know the value of x, substitute 21 for x:
[tex]l=21+5[/tex]
Add:
[tex]l=26\text{ cm}[/tex]
So, the length is 26 centimeters.
And we're done!