Precalculus (6th Edition) Blitzer

The number of years watching TV: $9.$ The number of years sleeping: $28.$
The number of years watching TV: $x$ The number of years sleeping: $x+19$ Total = $x+(x+19)=2x+19.$ We are given that the total is 37. $2x+19=37 \qquad$ ... subtract $19$ $2x=37-19$ $2x=18 \qquad$ ... divide with 2 $x=9$ $(x+19=9+19=28)$ The number of years watching TV: $9.$ The number of years sleeping: $28.$