For what values of the variable does the following expression make sense: square root of -10b

Asmall foreign car gete 42 miles per gallon and user 35 gallons on a trip.gasoline costs $1.05 per gallon.what was the cost of gasoline per mile driver?

Given abcd ac=38 and ae=3x+4 find the value of x

If there are 825 students at cherry hill high school and 4 out of every 5 students voted in the student council election, how many students voted?