SOLUTION: I am trying to find a solution to a problem for my 7th grader that has me confused.
I have a rectangle.
The long side "length" is 3x + 4 and the short side "width" is x - 2
Question 1108651: I am trying to find a solution to a problem for my 7th grader that has me confused.
I have a rectangle.
The long side "length" is 3x + 4 and the short side "width" is x - 2.
The perimeter is 20.
I have to figure the value of x.
I came up with the value of 2 for x.
If that is correct that the rectangle would have 2 sides of 10cm
And 2 sides of 0. Please help.
_____3x_+4_________
|
|x -2
|_________________|
P = 20. Solve for x
Perimeter = L + W + L + W
20 = (3x+4) + (x-2) + 3x+4) + (x-2),
20 = 8x + 4,
20 - 4 = 8x ====> 8x = 16 ====> x = = 2.
Answer. x = 2.
Solved.
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website! Perimeter = 2L + 2W. Agreed? If so:
2(3x + 4) + 2(x - 2) = 20
Distributive Law of multiplication:
6x + 8 + 2x - 4 = 20
Group similar:
6x + 2x + 8 - 4 = 20
8x + 4 = 20
Subtract 4, both sides:
8x = 16
x = 2
-------------------------------
Check:
2(3 * 2 + 4) + 2(2 - 2) = 20
2(6 + 4) + 4 - 4 = 20
12 + 8 + 4 - 4 = 20
20 + 0 = 20 Correct
Answer by TeachMath(96) (Show Source): You can put this solution on YOUR website! Something's wrong with one or both expressions, or the length of the perimeter. x is definitely equal to 2, but it doesn't make sense since that will make the shorter side 0, and which will leave 2 lines measuring 10 units each. That's not a rectangle.