Question 389447
Let W be the width of the rectangle.
Let L be the length of the rectangle.

The length is 3 cm more than twice its width. Therefore:
L = 2W + 3

The perimeter of the rectangle is 34 cm. Therefore: 
2W + 2L = 34

We can substitute the value of L from the first equation into the second:

2W + 2(2W + 3) = 34
Distributing the 2 on the right:
2W + 2*2W + 2*3 = 34
2W + 4W + 6 = 34
6W + 6 = 34
Subtracting 6 from both sides:
6W + 6 - 6 = 34 - 6
6W = 28
Dividing both sides by 6:
{{{6W/6 = 28/6}}}
{{{W = 28/6}}}
{{{W = 14/3}}} or,
W = 4 and 2/3 

We can substitute this value of W back into the first equation 
to find the value of L:

L = 2*W + 3
{{{L = 2*(14/3) + 3}}}
{{{L = 28/3 + 3}}} or,
L = 9 and 1/3 + 3 so,
L = 12 and 1/3