Advanced Math practice question

Answer: -0.25 or -1/4

x² = x + c gives x² − x − c = 0, which has one solution when 1 + 4c = 0, so c = −1/4.

Common wrong answers

If you answered 0

0 gives two intersections, at x = 0 and x = 1.

If you answered 1

1 gives two intersections.

If you answered 0.25

0.25 has the sign wrong.

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