Let the unknown number be "x".
Let's break apart the word problem.
• "The sum of a number and eight" can be written as

• Six times "the sum of a number and eight" can be written as:

• All of this is equal to 30, so we can write the final equation:

With the help of a little algebra, we can solve for "x" (the unknown number). The steps are shown below:

The
number is - 3