0) dan bought 7 new baseball trading cards to add to his collection. the next
day his dog ate half of his collection. there are now only 38 cards left.
how many cards did dan start with ?

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.