Question

A certain positive number is multiplied by 4, and then the result is subtracted from the original number. The result is 21 less than 0. What is the number?

Answer 1

Answer:

The number is 7

Step-by-step explanation:

certain positive number: x

x is multipled by 4:

4x

result of this is subtracted from the original number:

so original number minus 4x,

x - 4x

the result is 21 less than 0, this means negative 21

x - 4x = 0 - 21 = -21

do algebra:

-3x = -21

multiply both sides by -1

3x = 21

divide both sides by 3

x=7

(certain positive number: x) is equal to 7

Answer 2

Answer:

The answer is 7

Step-by-step explanation:

Let the positive number x

Then multiply by 4 : 4x

Subtracted by the number which is x-4x

Then we have x-4x=-21

: -3x=-21

X= -21/-3

X= 7