Hoe do i get the answer? what do i do ? ?

Classify the following triangle check all that apply

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a

Solve for x: 5/3 x = 20/21 it's fraction. remember to simplify your fraction