Đáp án:
a) `(2x-1)(y-4)=-13`
`⇒ (2x-1)(y-4)=(-1).13=1.(-13)`
Xét:
TH1: ` 2x-1=-1⇒2x=0⇒x=0`
` y-4=13⇒y=17`
TH2: ` 2x-1=13⇒2x=14⇒x=7`
` y-4=-1⇒y=3`
TH3: ` 2x-1=1⇒2x=2⇒x=1`
` y-4=-13⇒y=-11`
TH4: ` 2x-1=-13⇒2x=-12⇒x=-6`
` y-4=1⇒y=5`
Vậy: ...
b) `(5x+1)(y-1)=4`
`⇒ (5x+1)(y-1)=1.4=(-1).(-4)=2.2=(-2).(-2)`
TH1: `5x+1=1⇒5x=0⇒x=0`
`y-1=4⇒y=5`
Th2: `5x+1=4⇒5x=3⇒x=3/5`
`y-1=1⇒y=2`
Th3: `5x+1=-1⇒5x=-2⇒x=-2/5`
`y-1=-4⇒y=-3`
Th4: `5x+1=-4⇒5x=-5⇒x=-1`
`y-1=-1⇒y=0`
Th5: `5x+1=2⇒5x=-1⇒x=-1/5`
`y-1=2⇒y=3`
Th6: `5x+1=-2⇒5x=-3⇒x=-3/5`
`y-1=-2⇒y=-1`
Vậy: ...