Đáp án:
a)$\left \{ {{x=2} \atop {y=1}} \right.$
b)$\left \{ {{x=\frac{14}{11} } \atop {y=\frac{-50}{33} }} \right.$
c)$\left \{ {{x=10} \atop {y=7}} \right.$
d)$\left \{ {{x=\frac{11}{19} } \atop {y=\frac{-6}{19} }} \right.$
e)$\left \{ {{x=2} \atop {y=-3}} \right.$
f)$\left \{ {{x=3} \atop {y=-2}} \right.$
Giải thích các bước giải:
a)⇔$\left \{ {{(2x-y)+(3x+y)=10} \atop {2x-y=3}} \right.$
⇔ $\left \{ {{5x=10} \atop {2x-y=3}} \right.$
⇔$\left \{ {{x=2} \atop {y=1}} \right.$
b)⇔$\left \{ {{4x+6y=-4} \atop {15x+6y=18}} \right.$
⇔$\left \{ {{(4x+6y)-(15x+6y)=-14} \atop {2x+3y=-2}} \right.$
⇔$\left \{ {{-11x=-14} \atop {2x+3y=-2}} \right.$
⇔$\left \{ {{x=\frac{14}{11} } \atop {y=\frac{-50}{33} }} \right.$
c)⇔$\left \{ {{3x-3y=9} \atop {3x-4y=2}} \right.$
⇔$\left \{ {{(3x-3y)-(3x-4y)=7} \atop {x-y=3}} \right.$
⇔$\left \{ {{x=10} \atop {y=7}} \right.$
d)⇔$\left \{ {{7x-3y=5} \atop {12x+3y=6}} \right.$
⇔$\left \{ {{(7x-3y)+(12x+3y)=11} \atop {4x+y=2}} \right.$
⇔$\left \{ {{19x=11} \atop {4x+y=2}} \right.$
⇔$\left \{ {{x=\frac{11}{19} } \atop {y=\frac{-6}{19} }} \right.$
e)⇔$\left \{ {{(3x+y)+(2x-y)=10} \atop {3x+y=3}} \right.$
⇔$\left \{ {{5x=10} \atop {3x+y=3}} \right.$
⇔$\left \{ {{x=2} \atop {y=-3}} \right.$
f)⇔$\left \{ {{4x+3y=6} \atop {4x+2y=8}} \right.$
⇔$\left \{ {{x=3} \atop {y=-2}} \right.$
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