For this case, the first thing we must do is define a variable.
We have then:
x: unknown number
We now write the equation that models the problem:

From here, we clear the value of x.
We multiply both sides of the equation by 2:

We subtract 30 on both sides of the equation:

Answer:
The value of the unknown number is given by:

Step 1. READ THE QUESTION CAREFULLY!!!!!!
Step 2. Turn the problem into equations.
Step 3. Substitute/Eliminate variables.
Step 4. Find the first variable.
Step 5. Replace the variable1 with its correct number.
Step 6. Get your variable2.
Step 7.Do steps 3-4 until you have all the variables.
Step 8. Double check.
And you are done!
Answer:
13, 18, 72
Step-by-step explanation:
let x-5 represent the first number, since the first number is 5 less than the third number. let x represent the third number. let 4x represent the third number, since it's four times greater than the third number.
set up an equation, and make it equal to 103:
x-5+x+4x=103
solve:
6x-5=103
6x=108
x=18
so, the third number is 18.
the first number is equal to x-5, so:
18-5=13
the second number is equal to 4x, so:
4(18)=72
so, the three numbers are 13, 18, and 72.