Solving Systems of Two Equations and Two Unknowns: Graphing, Substitution, and Elimination

We know how to solve algebraic equations, but what about systems that contain two equations? Is there a solution that satisfies both equations? There might be! Let's go over a few different strategies to find this solution.

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[PhoenxFire]

We had a teacher with a doctorate in mathematics. I wish she could have explained this so easily to us. Sometimes having a doctorate does not make one a good teacher. Thanks for making this easier to understand!

[adityadhardwivedi]

hello professor, when you're going to explain and start tutorials of calculus?
Actually I am very much excited for your super easy tutorials. Thanks for your efforts.😃😊

[CartoonKidOLLY]

YAY it feels so good to understand the concepts and then get the problems right! I love you david!

[pianoboyedm]

thank you so much, my professor goes way too fast and never directly answers our questions, this helped our class out ALOT

[Concon-bubp]

Thanks dude. really enjoyed the manipulation followed by elimination, very cleaver way to approach the problem

[avenger]

how can some one be so serious yet so lovable

[reemyziz]

With checking comprehension, some y values don’t share a LSM. Can we multiple just one equation by a number so it matches the other?

[Regular_Decorated_Emergency]

Thanks so much! I finally understand what to do if you can’t subtract y from y to get 0!

[lexielea]

Holy shit you just taught me something that actually made sense for once and I’m so happy thank you

[scout]

Bro you just saved me for my algebra quiz THANK YOU

[Carrymejane]

At school I was never able to understand the algebra method 'concepts' well, and I only realized it now. Because at school we only focus on solving equations. We don't understand in focus and detail the method 'concept' for doing this. We don't understand it in its entirety so we just 'know' that to solve the equation it is only necessary to just 'follow' what's teacher did. Actually teacher doesn't do something wrong they great at teaching but they fail to know whether each student automatically understands a method in detail

[is]

Does this work on any function? Ex. Trig, Polynomial etc.

[noemiflores]

Hi professor Can you explain how to do Proportional and Non Proportianl? Thanks

[vernie]

Can you explain where you got: if A = B and C = D then A + C = B + D and that it proves that it applies to the equation above? It makes sense by itself but how do I know if the two equations are in any way related to that logic and how it helps us in solving them?

[captaingaz]

You need to make1 on comparison method

[azizghalib]

Thank you professor. But could you elaborate on how does the logic of A+C=B+D relates to system of equations. In other words, what variable corresponds to which term.

[OkSid]

Certainly a very productive lesson! But it would be great to have more real life examples.

[nteproductions]

Could’ve used a lot of this yesterday on the PSAT

[marcodaniel]

I don’t know what’s going wrong but different methods are giving me different answers pls send help

[saniconeiljoshuac.]

What is the 2 equations are both positive?