Question

A rectangle' s length (2x+1)cm and it's width (2x-1)cm. If it's area is 15 cm ,find the value of x

Answer 1

GIVEN :
Length = 2x + 1
Breadth = 2x - 1
Area = 15

SOL :
Area = l * b
$15 = (2x + 1)(2x -1)$
$15 = 2x(2x - 1) + 1(2x - 1)$
$15 = 4 {x}^{2} - 2x + 2x - 1$
$15 = 4 {x}^{2} - 1$
$15 + 1 = 4 {x}^{2}$
$16 = 4 {x}^{2}$
$\frac{16}{4} = {x}^{2}$
$4 = {x}^{2}$
$\sqrt{4} = x$
$2 = x$