Algebra: Chapter 6, Lesson 8, page 286.
Solving Equations by Factoring
The principle of zero products states that: for any rational numbers a and b, if the product `ab = 0`, then `a=0` or `b=0` or both `a` and `b = 0`.
Factor and solve equations by using the following:
- Get `0` on one side of the equation using the addition property
- FACTOR the expression on the other side of the equation
- Set each factor equal to zero
- Solve each equation.
If we have an equation with `0` on one side and a factorization on the other side, we can solve the equation by finding the values that make the factors `0`. This is even easier!
Since we are solving quadratic equations (they are NOT linear because they have an exponent that is squared, `x^2`), we can have at MOST 2 solutions. We can have NO solutions, 1 solution or 2 solutions.
Remember to use all the techniques you know to factor!
Two of tonight’s homework problems solved by MrE are here! Just click it!
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Algebra 1a: Chapter 8 REVIEW! Make sure that you review:
1. Motion Problems
REMEMBER, diagrams are great to get you to understand what you are looking for. The tables in the book are also good techniques. The more pictures or diagrams you have, the better chance you have of understanding what steps you have to go through! GO SLOW!!
Here are some links to excellent D-R-T examples at the PurpleMath website. Its easier to link to these than show you the same thing!
2. Digit and Coin word problems.
Just remember to write the coin problems with the d (dime), q (quarter), n (nickel) preceeded by the value of the coin remembering that the d, q or n stand for the number of that type of coin. For example, `.05n + .10d = 2.05`. You can then multiply both sides by `100` to clear the decimals.
Remember too, that any 2-digit number can be expressed as `10x + y` where `x` is the digit in the tens place and `y` is the digit in the one (units) place. For example, the number `23` can be written as `10 * 2 + 3`. If we reverse the digits in the original number, the new number can be expressed as `10y + x`. The reverse of `23`, `32` can be written as `10 * 3 + 2`.
Here is a link for some examples of coin problems and here is a link for digit type problems (about 1/2 the way down the page)!
3. Solving Systems of Equations by Graphing
A set of equations for which a common solution is sought is called a SYSTEM OF EQUATIONS. A solution of a system of 2 equations in 2 variables (x, y) is an ordered pair that makes both equations true.
Take 2 linear equations and graph them (with at least 2 points for each linear equation) and where they INTERSECT is a “SOLUTION” to BOTH equations.
Pretty simple to do, but it can be time consuming in that you have to have graph paper and a ruler and some time ….
Here is a link with LOTS of examples from purplemath.com. It goes on for 2 pages so make sure that you see them both!