Agardener is planting two types of trees: type a is 9 feet tall and grows at a rate of 11 inches per year. type b is 7 feet tall and grows at a rate of 14 inches per year. algebraically determine exactly how many years it will take for these trees to be the same height.

Primary sources contain information

A. with the advantage of hindsight and the perspective of an outside observer and may be more objective.
B. provided by someone who's been through an event. It's a firsthand account that lends a unique perspective.
C. on statistics gathered after an important historical event.
D. on psychological information gathered from raw data from psychological tests.