Question 1167827: how do I solve the system of equations by the substitution method for
28x +7y = 12
-4x =y + 8
Answer by ikleyn(52787)   (Show Source):
You can put this solution on YOUR website! .
From the second equation, express y = -4x - 8 and substitute it into the first equation, replacing y there
28x + 7*(-4x - 8) = 12.
Simplify
28x - 28x - 56 = 12
-56 = 12.
You get a self-contradictory equation, which has no solutions.
Hence, the original system has no solutions, too.
Solved, answered and explained.
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On the Substitution method, Elimination method, Determinants' method for solving the systems
of two linear equations in two unknowns see the lessons
- Solution of the linear system of two equations in two unknowns by the Substitution method
- Solution of the linear system of two equations in two unknowns by the Elimination method
- Solution of the linear system of two equations in two unknowns using determinant
- Geometric interpretation of the linear system of two equations in two unknowns (*)
- Useful tricks when solving systems of 2 equations in 2 unknowns by the Substitution method
in this site.
Pay special attention to the lesson marked (*) in the list, since it contains important information, useful to you (!)
Also, you have this free of charge online textbook in ALGEBRA-I in this site
- ALGEBRA-I - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this online textbook under the topic "Systems of two linear equations in two unknowns".
Save the link to this online textbook together with its description
Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson
to your archive and use it when it is needed.
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