How to solve 11x-13y=89 and -11x+13y=107 by substitution

Chip worked at the animal shelter for 6 hours each week for several weeks. he worked for a total of 42 hours. which of the following can be used to find the number of weeks chip worked at the animal shelter?

"princess tower" in dubai is considered the world's tallest residential building, towering to 1 0 1 101 floors! t ( n ) t(n) models the number of tenants living on floor n n of the tower. what does the statement t ( 2 0 ) = t ( c ) t(20)=t(c) mean?

Find the average speed of a rabbit that runs a distance of 22 m in a time of 1.8 s .