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Learn it your way
A short class with Sarah and her students. The other ways are under More.
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Today, we will discuss linear equations in two variables. Can anyone tell me what a linear equation looks like?
Isn’t it something like ax + by = c?
Exactly! And this equation represents a straight line on a graph. Who can explain why these equations can have multiple solutions?
Because the line intersects the x and y axes at different points, so there are lots of coordinates that satisfy the equation!
Great insight! This is foundational for understanding systems of equations.
To remember what a linear equation in two variables looks like, you can think of the acronym 'LIT' for 'Linear in Two dimensions.'
Now let's dive into methods for solving these equations. What do you think the first method might be?
Maybe graphing them?
Correct! The graphical method involves plotting both equations and finding where they intersect. What happens at the intersection?
That point is the solution to the system of equations!
Yes! Now, let's discuss substitution next. Can anyone describe this method?
You solve one equation for one variable and use that in the other equation?
Exactly! And remember, for elimination, you either add or subtract the equations to eliminate one variable. To remember these methods, think 'GSE,' which stands for Graph, Substitute, Eliminate.
Let’s take an example now. We have the equations and . Who would like to solve this using the elimination method?
We can add both equations to eliminate . So, ?
Perfect! What do we get after simplifying?
That gives us , so .
Correct! Now substitute back into the first equation to find . What do we get?
Substituting, we get , which means .
Fantastic! The solution is . So, to recap, we used elimination to find our solution. Remember, 'Two methods lead to one answer!'
A relationship that can be expressed as ax + by = c.
Finding solutions by graphing and looking for intersection points.
Solving one equation for a variable and substituting into the other.
Adding or subtracting equations to eliminate a variable.
In equations, we solve for x and y, find their point where they meet; oh my!
Once upon a time, in maths land, x and y were best friends. They crossed paths on a graph and found their meeting point, a magical spot that told their story.
Remember 'GSE': Graph, Substitute, Eliminate for solving systems of equations!
Think of 'GSE' to recall to Graph, Substitute, and Eliminate for solving linear equations in two variables.
Term
Elimination Method
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Term
Graphical Method
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Term
Substitution Method
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Intersection Point
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An algebraic equation that forms a straight line when graphed, typically expressed as ax + by = c.
A technique for solving equations by plotting them on a graph to find their intersection.
A method of solving systems of equations by replacing one variable with its equivalent expression from another equation.
A strategy for solving systems of equations by adding or subtracting equations to eliminate one variable.
The point where two lines intersect, representing the solution of a system of equations.
This section covers how to solve linear equations in two variables using various methods.
In this section, we explore how to solve linear equations in two variables, which can represent an infinite number of solutions. We discuss methods such as graphical, substitution, and elimination methods, providing examples to illustrate these concepts.
In this section, we learn how to solve linear equations containing two variables, such as those in the form of . Unlike single-variable equations, these equations can have infinitely many solutions depicted graphically as straight lines on a coordinate plane.
To demonstrate the elimination method, consider the equations:
Using elimination, we add both equations to isolate one variable. This process yields and substituting back gives . Thus, the solution is .
Understanding how to solve linear equations in two variables is vital for tackling more complex algebraic problems and applying these skills to various real-life situations.