Writing down an equation in terms of x

Hey everyone. I'm having a maths exam tomorrow and I'm a little confused with this question.
It shows a quadrilateral and it states the lengths of the sides are all given in centimeters.
Each side is
x + 2
x + 3
x+ 7
x (by itself)
Then it asks to write an expression of the quadrilateral in terms of x and I put down;
x + 12 (is that correct?)

Then, it asks the perimeter of the quadrilateral is 40cm.

Write down an equation in terms of X.
And it then asks me to SOLVE the equation.

Please help? I'm not stupid I'm just not sure how to answer it!

I'm a very visual learner so I may be getting this wrong, but what you need to do is add the four sides

So you have x+2+x+3+x+7+x

You have to add up all the x's, so you'd have 4x, because you have four of them. (4x is not x times x times x so on, that would be x to the power of three)

Then you ad the numbers, so you have that right, 12.

You would end up with 4x+12=40 (because all the sides make 40)


To find x, you need to take away all of what you know. 40-12= 28
Now you have 4x=28 (I really hope you get this) because you have minused 12 from both sides, they're not needed any more

you now need to find one x, so devide both sides by four to get x=7

the trick is that whetever you do to one side, you have to do it to the other.

That's the best I can do, hope this helps!

x+12 would be wrong as each x has a 1 in front of it, so it would be 4x

it would be
(x)+(x+2)+(x+3)+(x+7)
rearrange and put variables and numbers to gether and you get
x+x+x+x+7+2+3
simplify and u get
4x+12(remember, if x is alone, it means it has a 1 in front of it, so its the same as 1x+1x+1x+1x)

If the Perimiter is 40 cm (equation for perimiter for quad. , is side + side + side + side)

so it would be

40 = 4x+12 (as u already simplified all the sides together)

subtract 12 from each side

28=4x

divide both sides by 4

7=x
ie
x=7

4x+12=40
4x=28
x=7