Yesterday I learned how to solve systems of linear equations by using substitution. In Mathland today we learned how to do the same by using elimination.
Method of elimination1. Obtain coefficients that differ only in sign
2. Add equations to eliminate a variable.
3. Back substitute to solve for second equation.
4. Check your solution!
Example 1
5x + 3y =9
2x-4y=14
If we chose to eliminate y, we will make sure they have opposite signs but the same variable. Therefore we have to multiply he first equation by 4 and the second equation by 3. Giving us:
20x + 12y = 36
6x - 12y = 42
We will then add the equations to only have x
26x = 78
X=3
If we plug the value of x back into an equation we can algebraicly find y
5(3) + 3y =9
3y = 6
Y=2
Example 2
Elimination is a very effective way of solving the variables for solving equations. I actually prefer using elimination rather than substitution whenever I can, but both are equally as effective and easy!
"Stay chill. Stay swag Mathland!"
This is such a clear and concise way of explaining substitution! I like your example of solving for the speed of wind and the speed of the airplane more than mine! You made it very neat and pretty to look at.
ReplyDeleteI like your explanations between steps on example 1. It makes it very easy to understand and is good to do on the first example of any new concept.
ReplyDeleteI really like your example of speed and wind problem, it helps me understand more for the concept.
ReplyDeleteClear example, shows the steps and easy to understand and review what we learned from while ago.
ReplyDelete