What number must i add to complete the square x^2+12x=40

Atriangle includes one angle that 72º. which pair could be the measures of the other two angles of the triangle? a. 9º, 9º b. 26º, 46º c. 53º, 55º d. 72º, 108º

Aschool puts on a play. the play costs $1,200 in expenses. the students charge $4.00 for tickets. there will be one performance of the play in an auditorium that seats 500 people. what is the domain of the function that shows the profit as a function of the number of tickets sold?  

How far could you drive on 50 gallons of gas