What value in place of the question mark makes the polynomial below a perfect square trinomial? 16x^2+? x+36

Me what is the value of x? showing work would be appreciated - ! : )

Marcus and cody both leave the park at the same time, but in opposite directions. if cody travels 6 mph faster than marcus and after 4 hours they are 64 miles apart, how fast is each traveling? solve using rare times time = distance.

Ateacher brought a pack of 17 batteries . each calculator uses 3 batteries . how many calculator can the teacher fill with batteries