Question 85591
1.  
Let w=width of rectangle
Then the length=2w+2

Perimeter=2w+2l, so:

52=2w+2(2w+2) get rid of parens

52=2w+4w+4 subtract 4 from both sides
52-4=2w+4w+4-4 collect like terms

48=6w  divide both sides by 6

w=8 cm--------------------width of rectangle

2w+2=2*8+2=18cm-------------------length of rectangle

CK
52=2w+2l
52=2*8+2*18
52=16+36
52=52

2.

3x>7x+20  subtract 7x from both sides

3x-7x>20 collect like terms
-4x>20  divide both sides by -4 (remember the inequality sign will reverse)

x<-5  You Graph.  Hint: got to x=-5 on the x-y axis and draw a vertical line.  x will always be to the left of that line.


 3.

3(x–4)>7x–9  get rid of parens

3x-12>7x-9  subtract 7x and add 12 to both sides

3x-12+12-7x>7x-7x-9+12  collect like terms
-4x>3  divide both sides by -4(inequality sign reverses, again)

x<-3/4 You graph--same as before


Hope this helps---ptaylor