It equals 8.4
Hope this answers ur question
Answer:
x=35, y=21
Step-by-step explanation:
A way to rewrite the first equation is 
after cross-multiplying, we get 3x=5y.
If we solve for one variable, we can substitute it into the other equation.
Let's solve for x.
3x=5y
x=(5/3)y
Now, we can substitute x=(5/3)y in the equation x+y=56.
(5/3)y+y=56
(8/3)y=56
y=21
Going back to x+y=56, we can now plug back in y, knowing that it is 21.
x+21=56
x=35.
There are 4 sides so add 4 sides
3x-4+3x-4+2x+3+2x+3=78
Combine like terms
10x-2=78
Add 2 to each side of the equation
10x=80
Divide by 10
X=8
Enter x into equation
3(8)-4=20
2(8)+3=19
Multiply by 2
20 x 2= 40
19 x 2 = 38
40 +38 =78
Side 1- 20
Side 2- 19
Side 3- 20
Side 4- 19