## Algebra: A Combined Approach (4th Edition)

2 $\times$ ( 8 + x ) = x - 20
Problem: Twice the sum of 8 and a number is the difference of the number and 20 Let's start from the beginning. Twice the sum means we should have 2 $\times$ ( some sum ) The sum = 8 and a number Let's call the number x so the sum = 8 + x Now, we have 2 $\times$ ( 8 + x ) "is" means = the difference of the number and 20 means we should subtract 20 from x so 2 $\times$ ( 8 + x ) = x - 20