Answer:
Take x = 10.2 in. or x = 10 in.
Step-by-step explanation:
Given :
Length = (2x+3) in.
Breadth = x in.
Also, the Area of Rectangle = 240 sq in.
We know that,
Area of Rectangle = length x breadth
240 = (2x+3) x
2x² + 3x = 240
2x² + 3x - 240 = 0
Solving 2x²+3x-240 = 0 by the Quadratic Formula .
According to the Quadratic Formula, x , the solution for Ax2+Bx+C = 0 , where A, B and C are numbers, often called coefficients, is given by :
- B ± √ B²-4AC
x = ————————
2A
In our case, A = 2
B = 3
C = -240
Accordingly, B² - 4AC = 9 - (-1920) = 1929
Applying the quadratic formula :
-3 ± √ 1929
x = ——————
4
√ 1929 , rounded to 4 decimal digits, is 43.9204
So now we are looking at:
x = ( -3 ± 43.920 ) / 4
Two real solutions:
x =(-3+√1929)/4=10.230 ≈ 10
or
x =(-3-√1929)/4=-11.730
We'll take x = +ve value for calculation of length and breadth.
Therefore,
Length = [2(10.2) + 3 ]
L = 23.4 in.
Breadth = 10.2 in.
OR
Length = [2(10) + 3]
L = 23 in.
Breadth = 10 in.
