Teckenregler

Teckenregler
\[ a + (-b) = a - b \]	\[ a-(-b) = a + b \]
\[ a\cdot(-b) = -ab = (-a)\cdot b \]	\[ (-a) \cdot (-b) =(-(-a))b = ab \]
\[ \frac{-a}{b} = \frac{a}{-b} = -\frac{a}{b} \]	\[ \frac{-a}{-b}= \frac{a}{b} \]

 

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\[ -(x + 1) - (2 + ( - 2x + 3)) \]

\[ \begin{align} \begin{align}\]