Can someone help me solve for x in geometry please

Brent needs to paint a logo made using two right triangles. the dimensions of the logo are shown below. what is the difference between the area of the large triangle and the area of the small triangle? (1 point) select one: a. 4.5 cm2 b. 8.5 cm2 c. 16.5 cm2 d. 33.0 cm2

Hi, can anyone show me how to do this problem? 100 points for this. in advance

An arithmetic series a consists of consecutive integers that are multiples of 4 what is the sum of the first 9 terms of this sequence if the first term is 0