Multiple choice

If one of the roots of the equation $x^2 +ax- b = 0$ is 1, then what is (a- b) equal to ?

  1. -1

  2. 1

  3. 2

  4. -2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If 1 is a root of x^2 + ax - b = 0, then 1^2 + a(1) - b = 0, which simplifies to 1 + a - b = 0. Therefore, a - b = -1.

AI explanation

Substitute x = 1 into the equation x^2 + ax - b = 0, yielding 1 + a - b = 0, which means a - b = -1. This shows the required value is -1.

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