What is the energy cost for 540 kilowat-hours of electricity

At a rate of $0.08 per kilowat-hour, the equation C= 0.08t gives the cost of a customer's electic bill using t kilowatt-hours of energy. What is the energy cost for 540 kilowat-hours of electricity?

Can you help say how a graph for y= -x2 + 1 would be? and state whether is is linear or not linear.

and can you do the same for y= -2x +-5

Would a graph for y=x2-3 be linear?


Is the equation y=x+1 linear or not linear?

1]
Cost = 0.08 * 540 = $43.2

2]
It is a curve. Non-Linear.
Non-Linear.

3]
Non Linear.

4]
y = x + 1 is Linear