SOLUTION: The length and breadth of a rectangular are (5X +3) and (3X-2)cm. Write down in terms of X, (a) the perimeter (b) area. If the area of the rectangle is 230cm²,find the value

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: The length and breadth of a rectangular are (5X +3) and (3X-2)cm. Write down in terms of X, (a) the perimeter (b) area. If the area of the rectangle is 230cm²,find the value       Log On


   

Question 971875: The length and breadth of a rectangular are (5X +3) and (3X-2)cm. Write down in terms of X,
(a) the perimeter
(b) area.
If the area of the rectangle is 230cm²,find the value of X and hence write down the perimeter of the rectangle.
Found 2 solutions by Boreal, anand429:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
P= 2L + 2W= 2(5X+3) + 2(3X-2) = 10X +6 +6X-4 =16X-2

AREA= L * W=15x^2-x-6
230=15x^2-x-6
15x^2-x-236=0
(15x+59) (x-4)=0
first term will not make sense, as x <0
x=4
Length is 23
width is 10
Perimeter is twice their sum, or 66.

Answer by anand429(138) About Me  (Show Source):
You can put this solution on YOUR website!
l=5x%2B3
b=3x-2
So, the perimeter = 2l%2B2b
=2%2A%285x%2B3%29+%2B+2%2A%283x-2%29
=16x%2B2 -----------(i)
And Area = l%2Ab
=%285x%2B3%29%2A%283x-2%29
=15x%5E2-x-6---------------(ii)
If area = 230 ,then
15x%5E2-x-6+=+230
=> 15x%5E2-x-236+=+0
=> x=4 (x can't be neagative since breadth will become negative.
So the perimeter = 16*4+2
= 66 cms