Question

If the sum of a number and seven is doubled, the result is four less than the number. Find the number.

Answer 1

-18

Explanation:

Let the number be x.

Double the sum of number and seven is equal to four less than the number.

Expressing it in equation form:

`\[2*(x+7)=x-4\]`

Simplifying the equation,

`\[=> 2x+14=x-4\]`

Collecting all terms containing x on one side,

`\[=> 2x-x=-14-4\]`

`\[=> (2-1)x=-18\]`

`\[=> x=-18\]`

Hence the required number is -18

Answer 2

Answer: the number is - 18

Explanation:

Let the number be represented by x.

If the sum of a number and seven is doubled, the result is four less than the number. The expression would be

2(x + 7) = x - 4

We would open the bracket on the left hand side of the equation by multiplying each term inside the bracket by 2. It becomes

2x + 14 = x - 4

Subtracting 14 and x from the left hand side and the right hand side of the equation, it becomes

2x + 14 - 14 - x =x - x - 4 - 14

x = - 18