The first few multiples of 8 are [8, 16, 24, 32, 40, 48, 56, 64, 72, 80] and the first few multiples of 10 are [10, 20, 30, 40, 50, 60, 70, 80, 90]. The first few multiples they share are [40, 80] making 40 the smallest multiple 8 and 10 have in common.

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:

4z⁴ + 6z⁴
(4 + 6)z⁴
10z⁴

Betty scored 93% on the test meaning she earned 93% of the possible points on the test. There were 90 possible points on the test so she earned 90 x 0.93 = 84 points. Each question is worth 3 points so she got \( \frac{84}{3} \) = 28 questions right.

A factor is a positive integer that divides evenly into a given number. For example, the factors of 8 are 1, 2, 4, and 8.

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

4\( \sqrt{7} \) x 2\( \sqrt{8} \)
(4 x 2)\( \sqrt{7 \times 8} \)
8\( \sqrt{56} \)

Now we need to simplify the radical:

8\( \sqrt{56} \)
8\( \sqrt{14 \times 4} \)
8\( \sqrt{14 \times 2^2} \)
(8)(2)\( \sqrt{14} \)
16\( \sqrt{14} \)