Question 972385
Find the point(s) of intersection of the line x - y = -6  and the circle  x2 + y2 = 18 by solving the system of equations.
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x - y = -6
y = x + 6
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x^2 + y^2 = 18
sub for y
x^2 + (x+6)^2 = 18
2x^2 + 12x + 36 = 18
x^2 + 6x + 9 = 0
*[invoke solve_quadratic_equation 1,6,9]
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There are always 2 solutions to a quadratic.
For this one, they are x = -3 and x = -3.
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