Answer:
540 ft^2.
Step-by-step explanation:
The area of the trapezoid = h/2 (10 + 18) = 14h.
By Pythagoras the height h = √(5^2 - 4^2) = 3.
So the area of the 2 trapezoidal bases = 2 * 14*3
= 84 ft^2.
Now we calculate the area of the four lateral rectangular sides:
= 10*12 + 18*12 + 2*5*12
= 456 ft^2.
Total area = 456 + 54
= 540 ft^2.
5x-2+3x=17+12x-23 combine like terms
8x-2=12x-6
-8x -8x
-2=4x-6
+6 +6
4=4x divide each side by 4
x=1
Answer: 
Step-by-step explanation:
For this exercise you need to remember:
1) The mulitplication of signs:

2) By definition, like terms contain the same variables with the same exponent.
Then knowing this, and given the equations:
and 
You must subtract the like terms, which means that you must subtract the numerical coefficients of each term.
Then, you get the result is:

Is the algebra, if so what type?
The squiggly lines and the 2 straight lines through to sides of the pentagon mean that they are congruent (equal in length).
So, to find the perimeter of a regular polygon, you add all of its sides together.
So, the perimeter= 4x-2+x-2+x-2+x+2+x+2
To simplify it, add all of the x's together.
4x+x+x+x+x=8x
Perimeter=8x-2-2-2+2+2
-2-2=-4-2=-6+2=-4+2=-2
Perimeter=8x-2
Reach out to me if you have any questions. I'd be glad to help! :)