HELP ASAP. I’m just trying to get a good grade so you might see my post a lot:) brainliest involved

Erin bought christmas cards for $2 each to send to her family and friends. which variable is the dependent variable?

What is the value for this expression? 2e-5

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