Question

length of a rectangle is 8 cm less than twice of its breadth perimeter is 56 find length and breadth​

Answer 1

Step-by-step explanation:

2[(8-2x)+x]=56

2[8-2x+x]=56

2[8-x]=56

16-2x=56

-2x=56-16

-2x= 40

-x=40/2

-x=20

x=-20

Answer 2

• Let breadth be M.

» Length of a rectangle is 8 cm less than twice of its breadth perimeter is 56.

• Length = 2M - 8

• Perimeter = 56

_______________ [ GIVEN ]

We know that ..

$\boxed{\bold{Perimeter\: of\: rectangle\: =\: 2(l\: +\: b)}}$

Here..

• l = Length = 2M - 8

• b = Breadth = M

Put the known values in above formula.

→ 56 = 2(2M - 8 + M)

→ 56 = 2(3M - 8)

→ 56/2 = 3M - 8

→ 28 = 3M - 8

→ 28 + 8 = 3M

→ 36 = 3M

→ 3M = 36

→ M = 36/3

→ $\boxed{M \:=\: 12}$

______________________________

• We have to find the length and breadth of the rectangle.

Length = 2M - 8

→ 2(12) - 8

→ 24 - 8

→ 16 cm

Breadth = M

→ 12 cm

______________________________

$\textbf{Length\:=\:16\:cm}$

$\textbf{Breadth\:=\:12\:cm}$

____________ [ ANSWER ]

_____________________________

✡ Verification :

Perimeter of rectangle = 2(l + b)

From above calculations we have l = 16 cm and b = 12 cm and Perimeter = 56 (given)

Put them in above formula

=) 56 = 2(12 + 16)

=) 56 = 2(28)

=) 56 = 56

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