Each week i save half my pocket money and i buy stamps for my collection with 1/3 of the pocket money. that leaves $3.21. how much do i spend on stamps?

Solve 3x-18=2y and 5x-6y=14 by elimination or substitution . show all !

Me asap on # : explain how factoring a trinomial, ax^2+ bx+ c, when a does not equal 1 different from factoring a trinomial when a = 1.

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?