integers finding solve

Question

The sum of a number, n, and nine is twelve less than four times the number.

Answer 1

let the number be n

sum of a number, n and 9=n+9

12 less than four times the number= 4n-12

 

so the equation is: n+9=4n-12. Then you solve for n

Group like terms: n-4n=-12-9

                           -3n=-21

divide both sides by -3: n=-21/-3=7

 

 

Prove: substitute 7 into the equation: 7+9=4(7)-12

                                                        16=16

                            

Answer 2

Let n = the number

 

The sum is the result of an adding numbers.

 

Sum of a number and nine = n + 9

Twelve less than four times the number = 4n - 12

'is' means equal

 

n + 9 = 4n - 12     (add '12' to both sides)

   +12        +12

 

n + 21 = 4n          (subtract 'n' from both sides)

-n           -n

 

      21 = 3n          (divide both sides by '3')

       3     3 

 

       7 = n