Giải các phương trình vi phân:
(1+y²)dx + (1+x²)dy = 0

Players on the school soccer team are selling candles to raise money for an upcoming trip. each player has 24 candles to sell. if a player sells 4 candles a profit of$30 is made. if he sells 12 candles a profit of $70 is made

Write the equations in logarithmic form 7^3=343

Find the length of the normal and the angle it makes with the positive x-axis. (see pictured below)