Find all integers that satisfy:
a^2 + b^2 > 0
a^2 + b^2 | 4ab

URGENT PLEASE

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

Can someone me out here number 4 plz

Which type of graph would allow us to compare the median number of teeth for mammals and reptiles easily