Alex has $25 in his savings account. He needs $150 to buy a new bicycle. He plans to deposit $12.50 per week into the account until he has enough money to buy the bicycle. How many weeks will it take him to reach the necessary amount?

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.

The equation is  125+22m=b