Aformula is expressed as d=a(2+kt). express k in terms of d, a and t

Which of these choices show a pair of equivalent expressions?

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me

Aliter of water contains about 3.35 x 10^25 molecules. a certain river discharges about 2.9x 10^8 l of water every second. about how many molecules does the river discharge every minute? write your answer in scientific notation