It's an expression that can be simplified to read
( 0.7 x 0.4 ) ( b³ x b⁹ )
= ( 0.28 ) ( b¹² ) = 0.28 b¹² .
7x20=140. 7x2000=14000. The only thing that changes the product of these numbers is the amount of zeros behind the 2. Since the only two numbers that affect the answer is the 7 and the 2. (7x2=14). The number of zeros behind the 2 affect how many zeros will be included in the product.
I believe that through deductive reasoning angle O is 64 degrees. The reason is it's bigger than angle R so that rules out 32 and 16 degrees, but it's not obtuse, so that rules out 128 degrees, thereby leaving you with 64. Hope this helps :)
The answer would be B.
For these, you plug in 8 where there ia a variable. 2(8)-1=15