Scientific Notation is a way to represent very large or very less real number into easier way so that we may able to use them into our calculations.
It consist of two part a part containing the real number in decimals and the other part which is multiplied to the first part is in the form of 10 raise to some power. this exponent can be either positive or negative If it is positive the complete number is greater than one and if the exponent is negative the number is less than one.
$15 rental fee added to the 12.75 per hour. you have to multiply the 12.75 times the amount of hours rented, which we don't know yet so that's variable x. then he has only $45 to spend so it has to be equal to or less than that.
