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1.) 2x^2 - 4x = y + 1
x + y = 1
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Express y = 1-x from the second equation, and then substitute it into the first equation replacing y. You will get
2x^2 - 4x = (1-x) + 1,
2x^2 - 4x = 2 - x,
2x^2 - 3x - 2 = 0.
Continue from this point.
For many other similar solved problems see the lesson
- Solving the system of algebraic equations of degree 2 and degree 1,
in this site.
Also, you have this free of charge online textbook in ALGEBRA-I in this site
- ALGEBRA-I - YOUR ONLINE TEXTBOOK.
The referred lesson is the part of this online textbook under the topic "Systems of equations that are not linear".