What are the solutions to the simultaneous equations of y equals -2x and x2 plus y2 equals 80?

1 Answer

Answer :

If: y = -2x then y ^2 = 4x^2If: x^2 + y^2 = 80 then x^2 +4x^2 = 80So: 5x^2 = 80Divide all terms by 5: x^2 = 16Square root both sides: x = -4 or +4By substitution into the original equation solutions are: (-4,8) and (4, -8)

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