What is the solution for-5n-8(1+7n)=-8?

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

Find the solution of system of equation y= x-4 y=4x+2

Shane can shovel the driveway in 4 hours, but if his sister it would take 2 hours. how long would it take taylor to shovel the driveway alone