nine times a number is 30 more than three times that number. find the the number

Question

can you solve this problem and explain the steps

Answer 1

9x=30+3x

6x=30

x=5

Answer 2

Hi Ronald,

 

To solve this you need to know:

1. "is" means =

2. "more than" means +

3. "a number" is letter x (because we don't know what number it is)

 

So . . .

 

9x = 30 + 3x         (9x means "nine times some unknown number")

 

6x = 30                 (subtract 3x from both sides of the equation . . .

                             you subtract because subtraction is the opposite of +)

 

 x = 5                    (divide both sides by 6 . . .

                               because division is the opposite of multiplication)

 

Then you can check the answer by substituting 5 back into the equation:

 

9(5) = 30 + 3(5)

  45 = 30 + 15

  45 = 45                It checks out!  Nice!

Answer 3

9X=300+3X

6X=30

x=5