1st:x
2nd x+2
3rd: x+4
(x)+(x+2) = 3(x+4)-31
distribute
2x+2 = 3x+12-31
2x+2 =3x-19
subtract 2x from each side
2 = x-19
add 19 to each side
21 =x
Answer: 21,23,25
Answer:
Part 1) 
Part 2)
a) 
b) 
c) 
Step-by-step explanation:
<u><em>The complete question in the attached figure</em></u>
Part 1) Write an expression for the perimeter of the shape
we know that
The figure is composed by a larger square, a rectangle and a smaller square
1) The area of the larger square is given

so
The length and the width of the larger square is x units
2) The area of the rectangle is given

so
The length of the rectangle is x units and the width is 1 unit
3) The length and the width of the smaller square is x units
see the attached figure N 2 to better understand the problem
Find out the perimeter
The perimeter is the sum of all the sides.
so


Part 2) Find the perimeter for each of the given values of x.
a) For x=7 units
Substitute the value of x in the expression of the perimeter

b) For x=5.5 units
Substitute the value of x in the expression of the perimeter

b) For x=7/3 units
Substitute the value of x in the expression of the perimeter

The quick and easy answer is 3/100