13. If ax + bx - 9 =(x - k)(2x+k) and b>0
then k is equal to...
please please help! :))

If a baseball player hits a baseball from 4 feet off the ground with an initial velocity of 64 feet per second, how long will it take the baseball to hit the ground? use the equation h = −16t2 + 64t + 4.

The measures of the legs of a right triangle are 15m and 20m . what is the length of the hypotenuse

What is the 17th term in the arithmetic sequence in which a6 is 101 and a9 is 83