[tex] \left \{ {{x1-x2=1} \atop {x1+x2=2}} \right. [/tex] ⇒ [tex] \left \{ {{x1-x2=1} \atop {2x1=3}} \right. [/tex] ⇒ [tex] \left \{ {{x2=1,5-1} \atop {x1=1,5}} \right. [/tex] ⇒ [tex] \left \{ {{x2=0,5} \atop {x1=1,5}} \right. [/tex]
m=x1*x2⇒m=0,5*1,5=0,75