Today we covered Section 7.3 and 7.4 from the book, about solving a linear system y linear combination, and the applications of linear systems.

To step a linear system by combinations, follow the following 4 steps:

1. Arrange the equations with like terms in columns;

2. Multiply one or both of the equations by a number to obtain coefficients that are opposites to one of the variables;

3. Add the equations from Step 2. Combining like terms will eliminate one variable. Solve the remaining variable;

4. Substitute the value obtained from Step 3 into either of the original equations and solve for the other variable;

5. Check the solution in each of the orginal equations.

We did some classroom exercises together. Thanks go to those students who volunteered. As I told them, don’t be afraid to make mistakes and it is totally OK to make mistake.

We talked about the importance of the last step, to check, as this is the step where you can find out if you have made any mistake, and get a chance to fix the mistake.

For the word problems, we talked about three steps to come up with the equations:

1. Have a verbal model by drawing squares with words in them;

2. Pick variables x and y to represent some values;

3. Come up with the algebraic model which contains two equations.

Then use any approach to solve the equations.

For homework, find it below:

http://blog.newtonchineseschool.org/wangweidong/files/2011/09/Math7_Fall_HW_L2.pdf

I have given back to the students the skill reviews we did in the last Sunday. You can review it with your kid.

Again, feel free to contact me for any question.