Ron made a mistake casting a spell, and 25 frogs start to appear each second in the classroom. After 10 seconds, Hermione cast another spell, and 35 frogs start to disappear as 25 frogs appear each second. For how many seconds was there at least one frog in the classroom?

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

Lance lived in portugal and brazil for a total of 14 months to learn portuguese. he learned an average of 130 new words per month when he lived in portugal, and an average of 150 new words per month when he lived in brazil. in total he learned 1920 new words. write a system of equations to represent the situation. use x to represent portugal, and y to represent brazil

Which of the following graphs could represent a cubic function?