The simple way of calculating a perimeter is to add all of the sides.
For a rectangle this would equal 2 x length + 2 x width
P = 2(6x + 3) + 2(-2x - 5)
= 12x + 6 - 4x - 10
= 8x - 4
At a higher level both the length and width must be greater than zero (= zero is a trivial rectangle)
6x + 3 > 0
6x > -3
x > -0.5
-2x - 5 > 0
2x + 5 < 0 (multiplying by -1 reverses the inequality)
2x < -5
x < -2.5
This rectangle cannot exist as x cannot be < -2.5 and > -0.5 at the same time!
Answer:
A = -12
B = -8
C = -4
Step-by-step explanation:

x = -2

A = -12
x = 0

B = -8
x = 2

C = -4
Hope this helps
1.666666666666667 to be exact, but rounded it is 1.66
Step-by-step explanation:
1) 165⁰
2) 180⁰
Note:FOR initial temperature check the temperature at t=0
I hope it helped you