Because Marco already has 75 pounds of salt, he needs 200 – 75 = 125 additional pounds. Estimate the number of bags he needs. 125 is close to 120, and 120 ÷ 30 = 4, so he must need more than 4 bags (because 125 is more than 120). This means that Marco needs at least 5 more bags. Therefore, the correct answer is (B).

Whenever there are variables in the question and in the answers, think Plugging In. Let d = 2. The number of subscribers the website has signed up so far can be calculated as 500(2) = 1,000. Therefore, the website needs to sign up 100,000 – 1,000 = 99,000 additional subscribers. Plug 2 in for w in the answers to see which answer equals the target number of 99,000. Choice (A) becomes W = 500(2) = 1,000. This doesn’t match the target number, so eliminate (A). Choice (B) becomes W = 99,500(2) = 199,000. Eliminate (B). Choice (C) becomes W = 100,000 – 500(2) = 100,000 – 1,000 = 99,000. Keep (C), but check (D) just in case it also works. Choice (D) becomes W = 100,000 + 500(2) = 100,000 + 1,000 = 101,000. Eliminate (D). The correct answer is (C).

Since the question states f(4) = 5, then when x = 4, the result should be 5. Plug in x = 4 into each answer choice to see which equation does NOT equal 5. Choice (A) becomes f(4) = 4 + 1 = 5. This works, so eliminate (A). Choice (B) becomes f(4) = 2(4) – 3 = 8 – 3 = 5. Eliminate (B). Choice (C) becomes f(4) = 3(4) – 2 = 12 – 2 = 10. The correct answer is (C).

Start with the easier equation first and use Process of Elimination. The easier equation has to do with the total number of solutions. According to the question, Régine measures a total of 100 solutions. This information can be expressed as x + y = 100. Eliminate (B) and (C) because neither of these answers includes this equation. Remember that percentage means divided by 100. Therefore, 40% = 0.4 and 70% = 0.7. Given this information, x should be associated with 0.4 and y should be associated with 0.7. On this basis eliminate (D). The correct answer is (A).

The graph shown is a regular parabola that has been turned upside down and moved down 6. The equation of a regular parabola that points upward is y = x². Therefore, the graph of a parabola that points downwards is y = -x². Eliminate (D) because that answer is missing the negative sign. To move a parabola down 6 units, a 6 must be subtracted from the equation of the parabola. Eliminate (A) and (C), which add 6 instead. Choice (B) can be rewritten as y = -x² – 6. The correct answer is (B).