Đáp án:
Giải thích các bước giải:
a) ( x – 1)( y + 1) = 5
th1 :
$\left \{ {{x-1=5} \atop {y+1=5}} \right.$
<=> $\left \{ {{x=6} \atop {y=4}} \right.$
th2
$\left \{ {{x-1=-5} \atop {y+1=-5}} \right.$
<=> $\left \{ {{x=-4} \atop {y=-6}} \right.$
b) (x+2)(y-1) = 3
th1
$\left \{ {{y-1=3} \atop {x+2=3}} \right.$
<=> $\left \{ {{y=4} \atop {x=1}} \right.$
th2
$\left \{ {{y-1=-3} \atop {x+2=-3}} \right.$
<=> $\left \{ {{y=-2} \atop {x=-5}} \right.$
c) (3-x)(xy+5) = -1
th1 :
$\left \{ {{xy+5=-1} \atop {3-x=1}} \right.$
<=> $\left \{ {{y=-3} \atop {x=2}} \right.$
th2 :
$\left \{ {{xy+5=1} \atop {3-x=-1}} \right.$
<=> $\left \{ {{y=-1} \atop {x=4}} \right.$
Biết thế thui
