Karen works for $10 an hour. a total of 25% of her salary is deducted for taxes and insurance. she is trying to save $450 for a new set of tires. write an equation to determine how many hours she must work to take home $450 if she saves all of her earnings.

Ok, so they want an equation to help determine how many hour she must work to take home $450 dollars if she saves all of her earnings
We will let x represent the work hours

10x - (10x * .25) = 450

Now solve for x
10x - (10x * .25) = 450
10x - 10x * -.25 = 450
7.5x = 450
7.5x/7.5 = 450 / 7.5
x = 60 

So she will need to work 60 hours.

If you need help understanding how I derived at this conclusion, let me know.