-6x + 3x = -21 solving for variable

Omar is going on a road trip! the car rental company offers him two types of cars. each car has a fixed price, but he also needs to consider the cost of fuel. the first car costs $90 to rent, and because of its fuel consumption rate, there's an additional cost of s0.50 per kilometer driven.

Write an expression that represent sarah’s total pay last week.represent her hourly wage with w monday 5 tuesday 3 wednesday 0 noah hours wednesday 8 only with w wage did noah and sarah earn the same amount last week?

Prove sin2a + cos2a - 1 / sin2a + cos2a + 1 = 1 - tana / 1 + cota