Can someone figure this out??

What number should be added to the expression x^2+3x+ in order to create a perfect square trinomial? 3/2 3 9/4 9

Cody started biking to the park traveling 15 mph, after some time the bike got a flat so cody walked the rest of the way, traveling 4 mph. if the total trip to the park took 6 hours and it was 46 miles away, how long did cody travel at each speed? solve using rate times time= distance

The scatterplot represents the total fee for hours renting a bike. the line of best fit for the data is y = 6.855x + 10.215. which table shows the correct residual values for the data set?