During the cold winter months, a sheet of ice covers a lake near the arctic circle. at the beginning of spring, the ice starts to melt. the variable s models the ice sheets thickness in meters t weeks after the beginning of spring s=-0.25t+4 by how much does the ice sheets thickness decrease every 6 weeks

The answer is 76° i believe

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.