Answer:
The lengths of the sides of the rectangle are 13 inches and 15 inches
Explanation:
The perimeter of a rectangle
Given the two sides of a rectangle a and b. The perimeter of the rectangle is:

We are given the perimeter of a rectangle as:

And each side has a length of 3x+4 and 4x+3. Calculating the perimeter:

We set up the equation:

Dividing by 2:

Operating:

Subtracting 7x:

Subtracting 4:
x=3
The length of each side is:
3x+4=3*3+4=13
4x+3=4*3+3=15
The lengths of the sides of the rectangle are 13 inches and 15 inches