1 Solving linear equations：解线性（一次）方程
Solve for k:
k + 22 = 29
k = 这道题很简单，轻而易举的我们就知道答案是7。
2 Linear and quadratic systems直线和二次方程
.Which of the following equations combines with the graphed equation to create a system of equations whose solution set is comprised of the points (−1,−5) and (3,3)?
Please choose from one of the following options.
D. y=x2−4 其实我们能读懂题目就知道只是在说求与直线y=2x-3相交于（-1，-5）和（3,3）两点的一元二次方程，我们带入求解，很容易找到答案是A。
3 Data collection and conclusions：数据收集和结论
The graph above shows the results of a controlled experiment designed by a scientist to determine the effect of magnetic field strength on the growth of sunflower plants. 500 young sunflower plants were randomly assigned to the control or experimental group. In the control group, the scientist grew 250 sunflower plants under normal local geo-magnetic field conditions(30 microteslas). In the experimental group, the scientist grew 250 sunflower plants identically except under a lower geomagnetic field (20 microteslas). Based on the results of this experiment, which conclusion is NOT valid?
A.Sunflower plants grown under lower magnetic field conditions were more likely to weigh more than sunflower plants grown under normal magnetic field conditions.
B.There is evidence of an association between the strength of magnetic field and height in sunflower plants.
C.Sunflower plants grown under lower magnetic field conditions were more likely to be taller than sunflower plants grown under normal magnetic field conditions.
D.Members of the control group were more likely to grow to less than 100 inches than members of the experimental group.那我们根据数据分析的知识可以得到正确的答案是A.
4.A researcher representing a city government wants to measure public opinion about recycling by asking 1,000 randomly selected residents a series of questions on the subject. Which of the following is the best description of the research design for this study?
D.None of the above
5.A writer for a high school newspaper is conducting a survey to estimate the number of students that will vote for a particular candidate in an upcoming student government election. All students at the high school are eligible to vote in the election, and the writer decides to select a sample of students to take the survey. Which of the following sampling methods is most likely to produce valid results?
A.Survey every fifth student to enter the school library.
B.Survey every fifth student to arrive at school one morning.
C.Survey every fifth senior to arrive at school one morning.
D.Survey every fifth student to enter the school stadium for a football game.