[I am out of town and this class was taught by our substitute teacher Zheng Laoshi]

We further study solving linear inequalities using the properties we learned last time. We look at applications of simple inequalities.

Homework:

Page 18. #8 – #13, #20, #23 – #25.

We study simple linear inequalities. Unlike a simple linear equation where there is always one and only one solution, a linear inequality can have many solutions. We study the properties of ineqaulities:

If a > b, and k > 0, then ak > bk.

If a > b and k < 0, then ak < bk.

If a > b, then a + c > b + c.

If a < b, and b < c, then a < c.

The above properties are also true for cases of a >= b.

We talked about using the above properties to solve very simple inequalities like 4x < 28, or 3x >= 36.

Homework:

Page 17, #1 to #7, #14.

We study the slopes of line graphs, which is to measure the steepness of a straight line, and is defined to be ratio of y rise over x run, or the ratio of vertical change over the horizontal change.

We talk about the meaning of positive slope and negative slope. We study the special cases of horizontal line where the slope is always 0, and vertical lines where the slope is undefined.

We practice on how to calculate slopes based on the given information.

Homework:

Page 11, #9 to #17.

We introduce Cartesian Coordinate System, how to plot points in the coordinate system, the quadrants.

We look at linear graphs, how to draw them and interpret them.

Homework: Page 9, #1 – #8.

We focus on geometric sequences. A geometric sequence is a sequence where the ratio between any two consecutive terms is always the same. We usually use r to represent this common ratio.

So for a geometric sequence whose first term is a and whose common ratio is r, its nth term is:

an  = ar^(n-1)

Keep in mind that the complete sequence of a geometric sequence is determined by a particular term and the common ratio.

We did a bunch of exercises in the classroom.

Homework:

http://blog.newtonchineseschool.org/wangweidong/files/2014/09/HomeworkGeometricSequence.pdf

We focus on Arithmetic sequences. An arithmetic sequence is a sequence where the difference between any two consecutive terms is always the same. We usually use d to represent this common difference.

So for an arithmetic sequence whose first term is a and whose common difference is d, its nth term is:

an  = a + (n-1)d

Keep in mind that the complete sequence of an arithmetic sequence is determined by a particular term and the common difference.

We did a bunch of exercises in the classroom.

Homework: Workbook Page 4, #21, #22, #26, #27 and the following:

http://blog.newtonchineseschool.org/wangweidong/files/2014/09/HomeworkArithmeticSequence.pdf