Can someone me? and explain? , i'm so

What is the product of the radical expression. (7-2square root) (8+2 square root)

With this question! what is process of elimination? ? p. s. my brothers acc got banned so add his new one @ yamauchiyamyam17

In the diagram, the ratios of two pairs of corresponding sides are equal to prove that almn - axyz by the sas similarity theorem, it also needs to be shown that x 6 z un z zz un = 2x zləzz lezy