What is this need it quick

Let x = a + bi and y = c + di and z = f + gi. which statements are true?

Which of the following expressions cannot be simplified to x – 2?

The water company charges a residential customer $41 for the first 3,000 gallons of water used and $1 for every 200 gallons used over 3000 gallons. if the water bill was $58 how many gallons of water were usedanswersa 3400 gallonsb 6000 gallonsc 6400 gallons d 7000 gallons