-9(x+2)=54 apply the distributive property and simplify ​

How do you write something in scientific notation?

Tommy buys a sweater that is on sale for 40% off the original price. the expression p -0.4p can be used to find the sale price of the sweater, where p is the original price of the sweater. if the original price of the sweater is 50, what is the sale price?

Which has the greater energy, light of wavelength 519 nm or light with a frequency of 5.42 x 10^8 sec^-1?