Answer:
the length should be 28.5 cm.
Explanation:
i used the equation 2L+2W=P (or L+L+W+W=P)
(length + length +width + width = perimeter)
I plugged the given information into this equation so i had:
2L+(2L-14)=86
then i solved for L
(this is what that work would look like if you need it):
2L + 2(L - 14) = 86
1. distribute the 2 in 2(L-14):
2L + 2L - 28 = 86
2. combine like terms:
4L - 28 = 86
3. add 28 to both sides:
4L = 114
4. divide both sides by 4
L = 28.5
hope this helped :)