Tìm x,y thuộc Z
a, 19x2-84y2=1984
b, x2002-200y2001=2003
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a: =>x-xy+y=0
=>x(1-y)+1-y-1=0
=>(x+1)(1-y)=1
=>(x+1)(y-1)=-1
=>\(\left(x+1;y-1\right)\in\left\{\left(-1;1\right);\left(1;-1\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(-2;2\right);\left(0;0\right)\right\}\)
b: 2x-xy-2y=3
=>x(2-y)-2y+4=7
=>x(2-y)+2(2-y)=7
=>(x+2)(y-2)=-7
=>\(\left(x+2;y-2\right)\in\left\{\left(1;-7\right);\left(-7;1\right);\left(-1;7\right);\left(7;-1\right)\right\}\)
=>\(\left(x;y\right)\in\left\{\left(-1;-5\right);\left(-9;3\right);\left(-3;9\right);\left(5;1\right)\right\}\)
c: =>x(4-y)+5y-20=-3
=>x(4-y)-5(4-y)=-3
=>(4-y)(x-5)=-3
=>(x-5)(y-4)=3
=>\(\left(x-5;y-4\right)\in\left\{\left(1;3\right);\left(3;1\right);\left(-1;-3\right);\left(-3;-1\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(6;9\right);\left(8;5\right);\left(4;1\right);\left(2;3\right)\right\}\)
bạn đã k đủ 3k hẹn lần sau
Bai 1. tinh chat bac cau
bai 2> a) x=+-2003
b) >x=0
c)x=y=0
a: \(49-y^2=6\left(x-2021\right)^2\)
=>\(49-y^2\ge0\) và \(49-y^2\) ⋮6
=>\(y^2\in\left\lbrace1;16;25;49\right\rbrace\)
TH1: \(y^2=1\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-1=48\)
=>\(\left(x-2021\right)^2=8\)
mà x nguyên
nên x∈∅
TH2: \(y^2=16\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-16=33\)
=>\(\left(x-2021\right)^2=5,5\)
mà x nguyên
nên x∈∅
TH3: \(y^2=25\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-25=24\)
=>\(\left(x-2021\right)^2=4\)
=>x-2021=2 hoặc x-2021=-2
=>x=2023(nhận) hoặc x=2019(nhận)
\(y^2=25\)
=>y=5(nhận) hoặc y=-5(nhận)
TH4: \(y^2=49\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-49=0\)
=>\(\left(x-2021\right)^2=0\)
=>x-2021=0
=>x=2021(nhận)
\(y^2=49\)
=>y=7(nhận) hoặc y=-7(nhận)
a: \(49-y^2=6\left(x-2021\right)^2\)
=>\(49-y^2\ge0\) và \(49-y^2\) ⋮6
=>\(y^2\in\left\lbrace1;16;25;49\right\rbrace\)
TH1: \(y^2=1\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-1=48\)
=>\(\left(x-2021\right)^2=8\)
mà x nguyên
nên x∈∅
TH2: \(y^2=16\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-16=33\)
=>\(\left(x-2021\right)^2=5,5\)
mà x nguyên
nên x∈∅
TH3: \(y^2=25\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-25=24\)
=>\(\left(x-2021\right)^2=4\)
=>x-2021=2 hoặc x-2021=-2
=>x=2023(nhận) hoặc x=2019(nhận)
\(y^2=25\)
=>y=5(nhận) hoặc y=-5(nhận)
TH4: \(y^2=49\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-49=0\)
=>\(\left(x-2021\right)^2=0\)
=>x-2021=0
=>x=2021(nhận)
\(y^2=49\)
=>y=7(nhận) hoặc y=-7(nhận)
a: \(49-y^2=6\left(x-2021\right)^2\)
=>\(49-y^2\ge0\) và \(49-y^2\) ⋮6
=>\(y^2\in\left\lbrace1;16;25;49\right\rbrace\)
TH1: \(y^2=1\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-1=48\)
=>\(\left(x-2021\right)^2=8\)
mà x nguyên
nên x∈∅
TH2: \(y^2=16\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-16=33\)
=>\(\left(x-2021\right)^2=5,5\)
mà x nguyên
nên x∈∅
TH3: \(y^2=25\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-25=24\)
=>\(\left(x-2021\right)^2=4\)
=>x-2021=2 hoặc x-2021=-2
=>x=2023(nhận) hoặc x=2019(nhận)
\(y^2=25\)
=>y=5(nhận) hoặc y=-5(nhận)
TH4: \(y^2=49\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-49=0\)
=>\(\left(x-2021\right)^2=0\)
=>x-2021=0
=>x=2021(nhận)
\(y^2=49\)
=>y=7(nhận) hoặc y=-7(nhận)
a: \(49-y^2=6\left(x-2021\right)^2\)
=>\(49-y^2\ge0\) và \(49-y^2\) ⋮6
=>\(y^2\in\left\lbrace1;16;25;49\right\rbrace\)
TH1: \(y^2=1\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-1=48\)
=>\(\left(x-2021\right)^2=8\)
mà x nguyên
nên x∈∅
TH2: \(y^2=16\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-16=33\)
=>\(\left(x-2021\right)^2=5,5\)
mà x nguyên
nên x∈∅
TH3: \(y^2=25\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-25=24\)
=>\(\left(x-2021\right)^2=4\)
=>x-2021=2 hoặc x-2021=-2
=>x=2023(nhận) hoặc x=2019(nhận)
\(y^2=25\)
=>y=5(nhận) hoặc y=-5(nhận)
TH4: \(y^2=49\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-49=0\)
=>\(\left(x-2021\right)^2=0\)
=>x-2021=0
=>x=2021(nhận)
\(y^2=49\)
=>y=7(nhận) hoặc y=-7(nhận)
a: \(49-y^2=6\left(x-2021\right)^2\)
=>\(49-y^2\ge0\) và \(49-y^2\) ⋮6
=>\(y^2\in\left\lbrace1;16;25;49\right\rbrace\)
TH1: \(y^2=1\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-1=48\)
=>\(\left(x-2021\right)^2=8\)
mà x nguyên
nên x∈∅
TH2: \(y^2=16\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-16=33\)
=>\(\left(x-2021\right)^2=5,5\)
mà x nguyên
nên x∈∅
TH3: \(y^2=25\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-25=24\)
=>\(\left(x-2021\right)^2=4\)
=>x-2021=2 hoặc x-2021=-2
=>x=2023(nhận) hoặc x=2019(nhận)
\(y^2=25\)
=>y=5(nhận) hoặc y=-5(nhận)
TH4: \(y^2=49\)
Ta có: \(49-y^2=6\left(x-2021\right)^2\)
=>\(6\left(x-2021\right)^2=49-49=0\)
=>\(\left(x-2021\right)^2=0\)
=>x-2021=0
=>x=2021(nhận)
\(y^2=49\)
=>y=7(nhận) hoặc y=-7(nhận)