3.3 Lösning 1b
Från Mathonline
- \[\begin{array}{rclcl} 8 \;\, + \, \boxed{3\,x} & = & 17 & \qquad & {\rm Täck\;över\;} 3\,x \\ 8 \;\, + \, \boxed{\;\,?\;\,} & = & 17 & & \\ 8 \;\, + \, \boxed{\;\,9\;\,} & = & 17 & & \end{array}\]
- \[ \;\; \Downarrow \]
\( \; \begin{array}{rclcl} 3 \;\, \cdot \;\, x \; & = & 9 & \qquad & {\rm Täck\;över\;} x \\ 3 \;\, \cdot \; \boxed{x} & = & 9 & & \\ 3 \;\, \cdot \; \boxed{?} & = & 9 & & \\ 3 \;\, \cdot \; \boxed{3} & = & 9 & & \\ \end{array}\)
- \[ \quad\; \Downarrow \]
- \[ \, x \; = \; 3 \]
