First blank: not random Because he sent it to the top 5 students. Not random students throughout the grade.
second blank: I would guess not valid because it was not a random sample.
Answer:
A. 35
Step-by-step explanation:
Each week has 7 days, and we have 5 weeks.
Week 1 has 7 days.
Week 2 has 7 days.
Week 3 has 7 days.
Week 4 has 7 days.
Week 5 has 7 days.
We can add all these together to get the total number of days: 7 + 7 + 7 + 7 + 7 = 7 * 5 = 35.
Thus, the answer is A.
Hope this helps!
A. An organ is the oldest keyboard instrument.
You're looking for common multiples.
4: 4, 8, 12, 16, 20, 24, ...
6: 6, 12, 18, 24, ...
Since he is on the same machines today, he will be on the same machines again in 12 days.
<span><span>(<span><span>3x</span>+<span>−<span>7<span>y4</span></span></span></span>)</span><span>(<span><span>3x</span>+<span>−<span>7<span>y4</span></span></span></span>)</span></span><span>=<span><span><span><span><span>(<span>3x</span>)</span><span>(<span>3x</span>)</span></span>+<span><span>(<span>3x</span>)</span><span>(<span>−<span>7<span>y4</span></span></span>)</span></span></span>+<span><span>(<span>−<span>7<span>y4</span></span></span>)</span><span>(<span>3x</span>)</span></span></span>+<span><span>(<span>−<span>7<span>y4</span></span></span>)</span><span>(<span>−<span>7<span>y4</span></span></span>)</span></span></span></span><span>=<span><span><span><span>9<span>x2</span></span>−<span><span>21x</span><span>y4</span></span></span>−<span><span>21x</span><span>y4</span></span></span>+<span>49<span>y8</span></span></span></span><span>=<span><span><span>49<span>y8</span></span>−<span><span>42x</span><span>y4</span></span></span>+<span>9<span>x</span></span></span></span>
