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Hei jeg trenger litt hjelp med å forstå utregningen her:

[tex]\frac{r+2}{r+3}-\frac{r+2}{2r+1}=\frac{(r+2)\cdot(2r+1)-(r+2)\cdot(r+3)}{(r+3)\cdot(2r+1)}=\frac{(2r^2+5r+2)-(r^2+5r+6)}{2r^2+7r+3}=\frac{r^2-4}{2r^2+7r+3}[/tex]

Knuta skrev:[tex]\frac{r+2}{r+3}-\frac{r+2}{2r+1}=\frac{(r+2)\cdot(2r+1)-(r+2)\cdot(r+3)}{(r+3)\cdot(2r+1)}=\frac{(2r^2+5r+2)-(r^2+5r+6)}{2r^2+7r+3}=\frac{r^2-4}{2r^2+7r+3}[/tex]

Tusen takk for hjelpen