Find a point on the graph and plug that point into each of the answers to see which equation works. The graph goes through the point (0, -6). Using that point, (A) becomes -6 = 0² – 0 -6. Solve the right side of the equation to get -6 = -6. Keep (A), but check the remaining answer choices just in case. Choice (B) becomes -6 = 0 + 0 -12. Solve the right side of the equation to get -6 = -12. This is not true, so eliminate (B). Choice (C) becomes -6 = 0² + 6(0) + 9. Solve the right side of the equation to get -6 = 9. Eliminate (C). Choice (D) becomes -6 = 0² + 5(0) + 6. Solve the right side of the equation to get -6 = 6. Eliminate (D). The correct answer is (A).

The key to this problem is understanding that the three friends plan to climb an equal number of stairs. Start with the building for which we know the number of stairs. The friends are each planning to climb 3,639 ÷ 3 = 1,213 stairs. Since 1,213 must be a part of the correct answer, eliminate (B) and (D). Given that Dalia will complete only 75% of her goal, Dalia’s total must be multiplied by 75% or 0.75. This eliminates (C). The correct answer is (A).

Let’s break this question into smaller pieces. First, to find the number of U.S. residents who visit European countries every year, we will need to determine how many residents hold passports: 36% of 315 million = 0.36 × 315 = 113.4 million. Next, we can calculate how many of those passport-holders travel internationally each year: 8% of 113.4 million = 0.08 × 113.4 = 9.072 million. Finally, we can calculate how many of those international travelers visit Europe each year: 10% of 9.072 million = 0.1 × 9.072 = 0.9072 million. 0.9072 million is equivalent to 907,200, which is (C). The percentage calculations can also be done in one step: 0.1 × 0.08 × 0.36 × 315 = 0.9072 million.

Given that all of the answer choices are possible values for y, plug in the answers. In (A), y = x – 6. Plug this value into (x + 2)y² to get (x + 2)(x – 6)(x – 6). Multiply the last two factors together to get (x + 2)(x² – 12x + 36). Multiply the two resulting factors together to get x³ – 12x² + 36x + 2x² – 24x + 72. Combine like terms to get x³ – 10x² + 12x + 72. This is the same as the third degree polynomial in the question. Therefore, the correct answer is (A).

In 2010, as counted, there were 354 + 225 + 757 = 1,336 elephants in Wakanda. If the margin of error was 17.4, the lowest population of elephants that could fit within the margin of error would be 1,336 – 17.4 = 1,318.6 elephants. Because there cannot be fractional elephants, 1,319 is the smallest value that would be within the margin of error.