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1.1.4 Proof by contradiction (A-level only)

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Question 56

Assume that xxx and yyy are integers such that

x2−8y−6=0 x^2 - 8y - 6 = 0 x2−8y−6=0
a.

Prove that xxx is even.

[2]
b.

Hence, prove that 4y+34y + 34y+3 is even and explain why this leads to a contradiction.

[3]
c.

Explain what can be deduced about the integer solutions to the equation x2−8y−6=0x^2 - 8y - 6 = 0x2−8y−6=0.

[1]

1.1.4 Proof by contradiction (A-level only) Questions

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