Tìm các số nguyên x,y biết: a)2x(2y+3)–(2y+3)7b)x(y+4)–3(y+4)19c)xy–5x+2y–1031
Đọc tiếp
Tìm các số nguyên x,y biết:
a)2x(2y+3)–(2y+3)=7
b)x(y+4)–3(y+4)=19
c)xy–5x+2y–10=31
Những câu hỏi liên quan
Bài 10. Tìm số tự nhiên n, biết rằng: 1 + 2 + 3 + ..... + n = 820
Bài 11. Tìm các số tự nhiên x, y, sao cho:
a/ (2x+1)(y-3) = 10
b/ (3x-2)(2y-3) = 1
c/ (x+1)(2y-1) = 12
d/ x + 6 = y(x-1)
e/ x-3 = y(x+2)
f/ x + 2y + xy = 5
g/ 3x + xy + y = 4
Bài 12. Tìm số nguyên tố p sao cho:
a/ p + 2 và p + 4 là số nguyên tố
b/ p + 94 và p + 1994 cũng là số nguyên tố
Bài 1: Tìm x, y nguyên biết :
a) 4x + 2xy + y = 7
b) 3x - xy + 2y = 4
c) 2x + 3xy + y = -4
Bài 1: Tìm x, y nguyên biết :
a) 4x + 2xy + y = 7
=> 2.x(y-2)+(y-2)=5
=> ( y-2)(2x+1)= 5
Ta có bảng sau:
| 2x+1 | -5 | -1 | 1 | 5 |
| y-2 | -1 | -5 | 5 | 1 |
| x | -3 | -1 | 0 | 2 |
| y | 1 | -3 | 7 | 3 |
Điều kiện: t/m
Vậy:....
phần b và c tương tự
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b: =>x(3-y)+2y-6=-2
=>-x(y-3)+2(y-3)=-2
=>(y-3)(x-2)=2
=>\(\left(x-2;y-3\right)\in\left\{\left(1;2\right);\left(2;1\right);\left(-1;-2\right);\left(-2;-1\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(3;5\right);\left(4;4\right);\left(1;1\right);\left(0;2\right)\right\}\)
c: =>x(3y+2)+y+2/3=-4+2/3=-10/3
=>(y+2/3)(3x+1)=-10/3
=>(3x+1)(3y+2)=-10
=>\(\left(3x+1;3y+2\right)\in\left\{\left(1;-10\right);\left(10;-1\right);\left(-2;5\right);\left(-5;2\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(0;-4\right);\left(3;-1\right);\left(-1;1\right);\left(-2;0\right)\right\}\)
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Tìm các số nguyên x, y, biết:a) 3x 2y và x + y 10b)
x
−
2
y
+
3
4
6
và y - x -4c)
x
4
y
−
10
và x + 2y 12
Đọc tiếp
Tìm các số nguyên x, y, biết:
a) 3x = 2y và x + y = 10
b) x − 2 y + 3 = 4 6 và y - x = -4
c) x 4 = y − 10 và x + 2y = 12
a) x = 4; y = 6
b) x = 4; y = 0
c) x= -10; y= 25
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Tìm các cặp số nguyên x, y biết
a, x. ( y - 3) = - 4
b, xy - 3x - y = 0
c, xy + 2x + 2y = -16
Tìm các số nguyên x,y biết
a) xy+3x-2y-6=5
b) 5x+2y-xy=16
c) x+y=3 và x-y=15
d) |x|+|y|=1
a.
xy + 3x - 2y - 6 = 5
=>x(y + 3) - 2(y + 3) = 5
=>(x - 2)(y + 3) = 5.
Vì x, y thuộc Z nên x - 2, y + 3 thuộc Z
=> x - 2, y + 3 thuộc ước nguyên của 5
Lập bảng :
| x - 2 | -5 | -1 | 1 | 5 |
| y + 3 | -1 | -5 | 5 | 1 |
| x | -3 | 1 | 3 | 7 |
| y | -4 | -8 | 2 | -2 |
Vậy ......
b. Làm tương tự câu a.
c. Ta có x + y = 3 và x - y = 15
Bài này là tổng hiệu của cấp 1, áp dụng cách làm đó thì ta được số lớn là x = (3 + 15) : 2 = 9
Số bé là y = 9 - 15 = -6
d. Ta có : |x| + |y| = 1
=>|x| = 1 - |y|
Vì |x|, |y| >= 0 và |x| = 1 - |y| nên 0 =< |x|, |y| =< 1
Vì x, y thuộc Z nên x = 0 thì y = 1 hoặc -1 và ngược lại y = 0 thì x = 1 hoặc -1
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Mn help mik với!
Tìm số nguyên x, y biết:
a) (2x + 3)(y - 4) = 12 b) x(2y + 1) – 4y = 3 c) xy + 2x + y + 11 = 0
Tìm các số nguyên x, y , biết:a) 3x 2y và x + y 10b)
x
−
2
y
+
3
8
12
và
y
−
x
−
4
c)
x
2
y
5
và
x
+
2
y
12
Đọc tiếp
Tìm các số nguyên x, y , biết:
a) 3x = 2y và x + y = 10
b) x − 2 y + 3 = 8 12 và y − x = − 4
c) x 2 = y 5 và x + 2 y = 12
a) x + y = 10 ⇒ y = 10 − x ⇒ 3 x = 2 ( 10 − x ) ⇒ x = 4 ⇒ y = 6
b) y − x = − 4 ⇒ y = x − 4 ⇒ x − 2 x − 4 + 3 = 8 12 ⇒ x − 2 x − 1 = 8 12 ⇒ 12 x − 24 = 8 x − 8 ⇒ x = 4 ⇒ y = 0
c) x + 2 y = 12 ⇒ x = 12 − 2 y ⇒ 12 − 2 y 2 = y 5 ⇒ 60 − 10 y = 2 y ⇒ y = 5 ⇒ x = 2
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tìm các cặp số tự nhiên x, y biết:
xy+5x+5y=92xy+5x-2y=105xy-3x+2y-11=0xy-2x+y-4=0xy-x+2y-2=42xy+2x+3y=12nhanh minh tick
1. xy + 5x + 5y = 92
=> (xy + 5x) + (5y + 25) = 92 + 25
=> x(y + 5) + 5(y + 5) = 117
=> (x + 5)(y + 5) = 117
=> x + 5 \(\in\)Ư(117) = {-1;1;-3;3;-9;9;-13;13;-39;39;-117;117}
Mà x >= 0 => x + 5 >= 5
=> x + 5 \(\in\){9;13;39;117}
Ta có bảng sau:
| x + 5 | 9 | 13 | 39 | 117 |
| x | 4 | 8 | 34 | 112 |
| y + 5 | 13 | 9 | 3 | 1 |
| y | 8 | 4 | -2 (loại) | -4 (loại) |
Vậy; (x;y) \(\in\){(4;8);(8;4)}
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các câu còn lại tương tự như bài mình vừa làm
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Xem thêm câu trả lời
Bài 4: tìm x,y ϵ Z, biết:
a) (x - 3) (2y - 6) = 5
b) (2x + 1) (y + 2)= 10
c) xy - 5x + 2y = 7
d) xy - 3x - 4y = 5
a, \(x,y\in Z\Rightarrow\left\{{}\begin{matrix}x-3,2y-6\in Z\\x-3,2y-6\inƯ\left(5\right)=\left\{\pm1;\pm5\right\}\end{matrix}\right.\)
Ta có bảng:
| x-3 | -1 | -5 | 1 | 5 |
| 2y-6 | -5 | -1 | 5 | 1 |
| x | 2 | -2 | 4 | 8 |
| y | \(\dfrac{1}{2}\left(loại\right)\) | \(\dfrac{5}{2}\left(loại\right)\) | \(\dfrac{11}{2}\left(loại\right)\) | \(\dfrac{7}{2}\left(loại\right)\) |
Vậy không có x,y thỏa mãn đề bài
b, tương tự câu a
\(c,xy-5x+2y=7\\ \Rightarrow x\left(y-5\right)+2y-10=-3\\ \Rightarrow x\left(y-5\right)+2\left(y-5\right)=-3\\ \Rightarrow\left(x+2\right)\left(y-5\right)=-3\)
Rồi làm tương tự câu a
\(d,xy-3x-4y=5\\ \Rightarrow x\left(y-3\right)-4y+12=17\\ \Rightarrow x\left(y-3\right)-4\left(y-3\right)=17\\ \Rightarrow\left(x-4\right)\left(y-3\right)=17\)
Rồi làm tương tự câu a
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