# Algebra what is the actual answer ?

#### helpmeddddd

$$(a-b)^2=a^2-b^2$$

Which values of a and b show that this is not true?

#### Greens

$(a-b)^{2} = a^{2} -2ab + b^{2} = a^{2}-b^{2}$

Subtract $a^{2}$ both sides

$-2ab = -2b^{2}$

$a=b$

So just choose any $a$ and $b$ such that $a \neq b$ (edit) and $b \neq 0$ as Romsek mentioned

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#### romsek

Math Team
$(a-b)^2 = a^2 - 2ab + b^2$

$a^2 - 2ab + b^2 = a^2 - b^2$

$2b^2 = 2ab$

$\text{If$b = 0$this is true$\forall a$}$

$\text{otherwise$b=a$}$

$\text{So the original equation is only true if$b=0 \vee a=b$}$

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#### helpmeddddd

What if: $$(a â€“ b)^2= a^2â€“ b^2$$

Which values of a and b show that this is not true?

A. a = 1, b = 0 $\hspace{1cm}$ B. a = 1, b = 1

C. a = â€“1, b = â€“1 $\hspace{0.58cm}$ D. a = â€“1, b = 0

E. a = 1, b = â€“1

Thanks for those replies. How about this?

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E

#### [email protected]

You seriously can't plug in the values and see whether it equals??

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