An equation about a rectangle with given perimeter I am doing a revision calculator paper and am stuck on an algebra question. 
There is a picture of a rectangle. One side is $x-2,$ another side is $2x +1.$ 
The question is. Setup and solve an equation to work out the value of $x.$
The perimeter of this rectangle is $43$cm.
How do I do this? Sorry I am useless with algebra, and its worth 5 marks.
Thanks
 A: For the perimeter of a rectangle, we know that the perimeter is the sum of the lengths of all its sides. In a rectangle, opposite sides are equal in length. 
$$\text{Perimeter}\; = 2\times\;\text{length}\; + 2\times\;\text{width}$$
$$2(x - 2)+ 2(2x +1) =  \color{blue}{2x} \color{red}{\bf -4} + \color{blue}{4x} + \color{red}{\bf 2} =43$$
$$\color{blue}{6x}  \color{red}{\bf - 2} = 43$$
$$6x -2 + {\bf 2} = 43 + {\bf 2}$$
$$6x = 45$$
$${\
Khc 16} \times 6x = {\bf \dfrac 16} \times 45$$
$$ x = \dfrac {45}{6} = \dfrac{{\bf 3}\times 15}{{\bf 3} \times 2} =\dfrac {15}{2}$$
$$\text{This gives us}\;\;x = \frac{15}{2} = 7\frac12 = 7.5\;\text{cm}$$
A: The perimeter is the sum of the 4 sides of the rectangle. Hence $$43=2(x-2)+2(2x+1) \iff 43=2x-4+4x+2 \iff 43=6x-2 \iff 6x=45 \iff x=\frac{45}{6}$$
A: The perimeter $P$ of the rectangle has length 43, and we also know that the sum of the lengths of each edge is $(x-2)+(x-2)+(2x+1)+(2x+1)$. So, from this we get $P=43$ and $P=(x-2)+(x-2)+(2x+1)+(2x+1)$. So, $$(x-2)+(x-2)+(2x+1)+(2x+1)=43.$$ Can you simplify and solve this equation?
