%@Dif:2 %\SpecialCoor \par\vspace{1.5cm} \psovalbox{\rnode{A}{3}}\rnode{B}{\underline{$a$}}\psovalbox{+\rnode{C}{2}}\rnode{D}{\underline{$a$}}$=(3+2)\times a=$\rnode{E}{5}\rnode{F}{$a$} \hfill $x+3x=$\psovalbox{\rnode{A1}{1}}\rnode{B1}{\underline{$x$}}\psovalbox{+\rnode{C1}{3}}\rnode{D1}{\underline{$x$}}$=(1+3)\times x=$\rnode{E1}{4}\rnode{F1}{$x$} \hfill \psovalbox{\rnode{A2}{$-3$}}\rnode{B2}{\underline{$b$}}\psovalbox{$-$\rnode{C2}{5}}\rnode{D2}{\underline{$b$}}$=(-3-5)\times b=$\rnode{E2}{$-8$}\rnode{F2}{$b$} \ncarc[arcangle=60,offset=2mm]{<->}{A}{C} \naput{\rnode{G}{\footnotesize$3+2$}} \ncbar[nodesep=1mm,angle=90]{->}{G}{E} \ncarc[arcangle=-60,offset=-1mm]{<->}{B}{D} \nbput{\rnode{H}{}} \ncbar[angle=-90]{->}{H}{F} \ncarc[arcangle=60,offset=2mm]{<->}{A1}{C1} \naput{\rnode{G1}{\footnotesize$1+3$}} \ncbar[nodesep=1mm,angle=90]{->}{G1}{E1} \ncarc[arcangle=-60,offset=-1mm]{<->}{B1}{D1} \nbput{\rnode{H1}{}} \ncbar[angle=-90]{->}{H1}{F1} \ncarc[arcangle=60,offset=2mm]{<->}{A2}{C2} \naput{\rnode{G2}{\footnotesize$-3-5$}} \ncbar[nodesep=1mm,angle=90]{->}{G2}{E2} \ncarc[arcangle=-60,offset=-1mm]{<->}{B2}{D2} \nbput{\rnode{H2}{}} \ncbar[angle=-90]{->}{H2}{F2} \par\vspace{1cm}\par {\bf Attention, les expressions suivantes ne peuvent pas être réduites.} \[3\underline{a}+2\underline{b}\kern2cm 2\underline{a}+3\underline{\phantom{1}}\kern2cm2\underline{a^2}+5\underline{a}\] Recopie et complète les expressions suivantes : \[\Eqalign{ 3a+2a&=\hbox to 2.5cm{\dotfill}\kern1cm&x+5x&=\hbox to 2.5cm{\dotfill}\kern1cm&4a+2b&=\hbox to 2.5cm{\dotfill}\cr 5a+2&=\hbox to 2.5cm{\dotfill}&3b+7b&=\hbox to 2.5cm{\dotfill}&2a^2+3a^2&=\hbox to 2.5cm{\dotfill}\cr x^2+2x^2&=\hbox to 2.5cm{\dotfill}&4a^2+2a&=\hbox to 2.5cm{\dotfill}&4x-2x&=\hbox to 2.5cm{\dotfill}\cr -3x+5x&=\hbox to 2.5cm{\dotfill}&-2x-3x&=\hbox to 2.5cm{\dotfill}&-3x+2y&=\hbox to 2.5cm{\dotfill}\cr x-3x&=\hbox to 2.5cm{\dotfill}&2a-3a&=\hbox to 2.5cm{\dotfill}&-3a^2+5a^2&=\hbox to 2.5cm{\dotfill}\cr 4x-3x^2&=\hbox to 2.5cm{\dotfill}&-5x^2+2x^2&=\hbox to 2.5cm{\dotfill}&-c-c&=\hbox to 2.5cm{\dotfill}\cr -2c-c&=\hbox to 2.5cm{\dotfill}&-c-2&=\hbox to 2.5cm{\dotfill}&-2c-2c&=\hbox to 2.5cm{\dotfill}\cr 2x+2c&=\hbox to 2.5cm{\dotfill}&-x^2-4x^2&=\hbox to 2.5cm{\dotfill}&2y-y&=\hbox to 2.5cm{\dotfill}\cr 5y^2-2y^2&=\hbox to 2.5cm{\dotfill}&-2x^2-2x&=\hbox to 2.5cm{\dotfill}&3x-2x^2&=\hbox to 2.5cm{\dotfill}\cr }\]