## Introductory Algebra for College Students (7th Edition)

The number is $26$.
Let $x$ = the unknown number Then "twice a number" means $2x$ "sum of four and twice a number" means $4+2x$ Thus, the equation that represents the situation is: $4+2x=56$ Subtract $4$ on both sides of the equation to obtain: $2x=52$ Divide $2$ on both sides of the equation to obtain: $x=\dfrac{52}{2} \\x=26$