I wanted friends but got block by them can I be someone's friends on snap or something

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

Find the value of x for which the lines are parallel.

Water flows at a steady rate from a tap. its takes 40 seconds to fill a 4 litre watering can from the tap. the rate at which water flows from the tap is halved. complete: 4 litres into cm3