Plz answer quickly :))

Measures of the angle of r, 31 s (x+4) t (3x+9)

Two cyclists 84 miles apart start riding toward each other at the same. one cycles 2 times as fast as the other. if they meet 4 hours later, what is the speed (in mi/h) of the faster cyclist?

Look at this pattern ; 1,4,9, number 10000 belongs in this pattern . what’s the place of this number?