The greatest common factor (GCF) is the greatest factor that divides two integers.

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:

-1b² + 3b²
(-1 + 3)b²
2b²

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 15 workers at the company now and that's enough to staff 5 crews so there are \( \frac{15}{5} \) = 3 workers on a crew. 10 crews are needed for the busy season which, at 3 workers per crew, means that the roofing company will need 10 x 3 = 30 total workers to staff the crews during the busy season. The company already employs 15 workers so they need to add 30 - 15 = 15 new staff for the busy season.

To multiply terms with radicals, multiply the coefficients and radicands separately:

4\( \sqrt{5} \) x 9\( \sqrt{8} \)
(4 x 9)\( \sqrt{5 \times 8} \)
36\( \sqrt{40} \)

Now we need to simplify the radical:

36\( \sqrt{40} \)
36\( \sqrt{10 \times 4} \)
36\( \sqrt{10 \times 2^2} \)
(36)(2)\( \sqrt{10} \)
72\( \sqrt{10} \)

April scored 77% on the test meaning she earned 77% of the possible points on the test. There were 270 possible points on the test so she earned 270 x 0.77 = 207 points. Each question is worth 3 points so she got \( \frac{207}{3} \) = 69 questions right.