MA0001/Exercise 3/tasks/5.tex

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\begin{align*}
x^2+2x+2 &> 50 \\
(x+1)^2 + 1 &> 50 \qquad \text{(første kv. setning)} \\
(x+1)^2 &> 49 \\
x+1 &> \pm\sqrt{49} \\
\end{align*}
Vi deler opp likningen
\begin{align*}
-\sqrt{49} &< x+1 &&\vee& x+1 &< \sqrt{49} \\
-7 &< x+1 &&\vee& x+1 &< 7 \\
-8 &< x &&\vee& x &< 6 \\
\end{align*}
\[x \in \left(-8,6\right)\]