Help please Mathe question

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

Worth 15 points handsome jack is buying a pony made of diamonds. the price of the pony is p dollars, and jack also has to pay a 25% diamond pony tax. which of the following expressions could represent how much jack pays in total for the pony? a= p = 1/4 b= p+0.25p c=(p + 1/4)p d=5/4p 0.25p choose 2 answers

Awoman has 14 different shirts: 10 white shirts and 4 red shirts. if she randomly chooses 2 shirts to take with her on vacation, then what is the probability that she will choose two white shirts? show your answer in fraction and percent, round to the nearest whole percent.