help with writing math expressions

i need help with writing expressions

A) double the sum of 25 and 8

i think it is(2x25+8)

B) the quotient of 15 and 3 subtracted from the product of 4 and 9

i think it is (5/3-4x9)

C) the difference between 20 and 5 multiplied by the sum of 8 and 2

I think it is 20-5x8+2

D) 3 times the square root of the sum of

9 and 7 i think it is (3x9(2)+7(2)

(2) = squared as i don't know how to write that on a computer.

any help would be greatful or just letting me know i'm on the right track i just can't seem to get it (Doh)(Worried)