## Prealgebra (7th Edition)

To determine if a number is a solution for an equation, substitute the number for the variable and simplify to see if the equation is true. $2(26)-30-10$ $52-30=10$ $22=10\ X$ $2(40)-30-10$ $80-30=10$ $50=10\ X$ $2(20)-30-10$ $40-30=10$ $10=10\checkmark$