One number is 4 times a first number. A third number is 100 more than the first number. If the sum of the three numbers is 280, find the numbers. The three numbers are:

 The first number is 30.

The second number is 120.

The third number is 130

Step-by-step explanation:

x + 4x + x+ 100 = 280

6x = 280-100

6x= 180

x = 30

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.