In order to find how many additional workers are needed to staff the extra crews you first need to calculate how many workers are on a crew. There are 8 workers at the company now and that's enough to staff 2 crews so there are \( \frac{8}{2} \) = 4 workers on a crew. 7 crews are needed for the busy season which, at 4 workers per crew, means that the roofing company will need 7 x 4 = 28 total workers to staff the crews during the busy season. The company already employs 8 workers so they need to add 28 - 8 = 20 new staff for the busy season.

To add or subtract terms with exponents, both the base and the exponent must be the same. In this case they are so add the coefficients and retain the base and exponent:

-3z⁷ + 6z⁷
(-3 + 6)z⁷
3z⁷

To convert a negative exponent to a positive exponent, calculate the positive exponent then take the reciprocal.

If the tiger has consumed 49 pounds of food in 7 days that's \( \frac{49}{7} \) = 7 pounds of food per day. The tiger needs to consume 70 - 49 = 21 more pounds of food to reach 70 pounds total. At 7 pounds of food per day that's \( \frac{21}{7} \) = 3 more days.

The least common multiple (LCM) is the smallest positive integer that is a multiple of two or more integers.