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Advanced Math / Nonlinear equations in one variable and systems of equations in two variables Difficulty: Medium

x 2 + y + 10 = 10

8x+16-y=0

The solution to the given system of equations is x,y. What is the value of x ?

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Explanation

Choice B is correct. Adding y to each side of the second equation in the given system of equations yields 8 x + 16 = y . Substituting 8 x + 16 for y in the first equation yields x2+8x+16+10=10. Subtracting 10 from each side of this equation yields x 2 + 8 x + 16 = 0 . This equation can be rewritten as x+42=0. Taking the square root of each side of this equation yields x + 4 = 0 . Subtracting 4 from each side of this equation yields x = - 4 . Therefore, the value of x is - 4 .

Choice A is incorrect. This is the value of y , not x .

Choice C is incorrect and may result from conceptual or calculation errors.

Choice D is incorrect and may result from conceptual or calculation errors.