Respuesta :

lexy1338
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

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