Question

if 21 is added to a number it becomes 7 less than thrice of two numbers then the number is​

Answer 1

Answer:

answer is 14

Step-by-step explanation:

let the no. be x

x+21=3x-7

2x=21+7

x=28/2=14

Answer 2

Answer:

• The number is 14.

Step-by-step explanation:

Given that:

• If 21 is added to a number it becomes 7 less than thrice the number.

To Find:

• The number.

According to the question:

$\sf{\implies x+21=3x-7}$

Transposing variables on LHS, constants on RHS and changing their sign,

$\sf{\implies x-3x=-7-21}$

Subtracting,

$\sf{\implies -2x=-28}$

$\sf{\implies 2x=28}$

Transposing 2 from LHS to RHS and changing its sign,

$\sf{\implies x=\dfrac{28}{2}}$

Dividing the numbers,

$\sf{\implies x=14}$

Hence,

• x = 14

Therefore,

• The required number is 14.

Verification:

Substituting the value of x (14) in the equation and checking if LHS = RHS or not.

LHS:

$\sf{\dasharrow x+21}$

$\sf{\dasharrow14+21}$

$\sf{\dasharrow35}$

RHS:

$\sf{\dasharrow3x-7}$

$\sf{\dasharrow(3\times14)-7}$

$\sf{\dasharrow42-7}$

$\sf{\dasharrow35}$

As,

• LHS = RHS

Hence, Verified.