Work with a partner. you buy a shirt that is on sale for 30% off. you pay $22.40. your friend wants to know the original price of the shirt. how can your friend find the original price?

If a and b are the measures of two first quadrant angles and sin a = 4/9 and sin b = 2/5 find sin(a+b).

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

An initial investment of $100 is now valued at $150. the annual interest rate is 5%, compounded continuously. the equation 100e0.05t = 150 represents the situation, where t is the number of years the money has been invested. about how long has the money been invested? use your calculator and round to the nearest whole number. years