Name the property shown by the statement 5 +(a+8) =(5+a) +8

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

Which is the standard form for this number? (4 x 1 100 ) + (8 x 1 1,000 ) + ( 3 x 1 100,000 ) ? a) 0.004803 b) 0.04803 c) 0.0483 d) 0.483

Ill mark the brainliest if you me with the these three questions 7,8,9