[tex]a)\\\\\left \{ {{x+y=16} \atop {2x+y=9}} \right. \\\\\left \{ {{y=16-x} \atop {2x+16-x=9}} \right. \\\\\left \{ {{y=16-x} \atop {x=9-16}} \right. \\\\\left \{ {{x=-7} \atop {y=16-(-7)}} \right. \\\\\left \{ {{x=-7} \atop {y=23}} \right. \\\\sprawdzam:\\\\\left \{ {{-7+23=16} \atop {2\cdot (-7)+23=9}} \right. \\\\\left \{ {{16=16} \atop {9=9}} \right. \\\\\left \{ {{L=P} \atop {L=P}} \right. ~~~~cbdu[/tex]
[tex]b)\\\\\left \{ {{3x-y=10} \atop {x+y=16}} \right. ~~dodaje~~rownania~~stronami\\\\3x-y+x+y=10+16\\\\4x=26~~\mid \div 4\\\\x=6,5\\\\y=16-x~~\land~~x=6,5 ~~\Ryightarrow ~~y=16-6,5=9,5\\\\sprawdzam:\\\\\left \{ {{3\cdot 6,5-9,5=10} \atop {6,5+9,5=16}} \right. \\\\\left \{ {{19,5-9,5=10} \atop {16=16}} \right. \\\\\left \{ {{10=10} \atop {16=16}} \right. \\\\\left \{ {{L=P} \atop {L=P}} \right. ~~~~cbdu[/tex]
[tex]c)\\\\\left \{ {{6x-3y=6~~\mid \div 3} \atop {x+4y=8}} \right. \\\\\left \{ {{2x-y=2} \atop {x+4y=8}} \right. \\\\\left \{ {{y=2x-2} \atop {x+4\cdot (2x-2)=8}} \right. \\\\\left \{ {{y=2x-2} \atop {x+8x-8=8}} \right. \\\\\left \{ {{y=2x-2} \atop {9x=16} ~~\mid \div 9} \right. \\\\\left \{ {{x=\frac{16}{9} } \atop {y=2\cdot \frac{16}{9}-2 }} \right. \\\\\left \{ {{x=1\frac{7}{9} } \atop {y=3\frac{5}{9}-2 }} \right. \\\\\left \{ {{x=1\frac{7}{9} } \atop {y=1\frac{5}{9} }} \right. \\\\[/tex]
[tex]sprawdzam:\\\\\left \{ {{6\cdot \frac{16}{9} -3\cdot \frac{14}{9} =6} \atop {\frac{16}{9} +4\cdot \frac{14}{9} =8}} \right. \\\\\left \{ {{\frac{96}{9} -\frac{42}{9} =6} \atop {\frac{16}{9} +\frac{56}{9} =8}} \right. \\\\\left \{ {{\frac{54}{9} =6} \atop {\frac{72}{9} =8}} \right. \\\\\left \{ {{6=6} \atop {8=8}} \right. \\\\\left \{ {{L=P} \atop {L=P}} \right. ~~~~cbdu[/tex]
