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What is wrong with the following proof? Clearly we know that 1 does not equal 2. What rule of algebra did we break that makes th

Gnoma [55]

An attempt to divide by zero gives a contradictory result

A rule of algebra broken is <u>dividing by zero</u> (leading to a contradiction) and stating a finite result

Reason:

The given calculation is presented as follows;

1. a > 0, b > 0 given

2. a = b given

3. a·b = b²

4. a·b - a² = b² - a²

5. a·(b - a) = (b + a)·(b - a)

6. a = b + a

7. 0 = b

8. b = 2·b

9. 1 = 2

From line 4, the result are;

4. a·b - a² = b² - a² = 0

5. a·(b - a) = (b + a)·(b - a) = 0

On line 6, both sides where divided by (b - a) = 0, which should given an infinite result

Therefore, one rule of algebra broken is dividing by zero to get a finite result

In line 7, we have;

7. 0 = b

From 6. a = b + a, and a = b, we have;

8. b = 2·b

Therefore, line 9 should be;

9. 0 = 2·0; 0 = 0, given that we have;

1 × 0 = 0

2 × 0 = 0

∴ 1 × 0 = 2 × 0

However

1 ≠ 2

In line 9., by dividing by b = 0, again, we have;

9. 1 = 2 (a contradiction)

Therefore, one rule of algebra that is broken is <u>dividing by zero</u> and having a finite result

Learn more about the rules of algebra here:

brainly.com/question/11388301

5 0

2 years ago

Find the domain of f(x)=x-9/x squared-81

vagabundo [1.1K]

$f(x)=\dfrac{x-9}{x^2-81}\\\\\text{The domain:}\\\\x^2-81\neq0\qquad\text{add 81 to both sides}\\\\x^2\neq81\to x\neq\pm\sqrt{81}\\\\x\neq-9\ \wedge\ x\neq9\\\\Answer:\ \boxed{\text{All real numbers except -9 and 9}}\to\boxed{x\in\mathbb{R}-\{-9,\ 9\}}$