Tìm hai so nguyen duong a va b de \(Q=\frac{1}{a}+\frac{2}{b}\) nhan gia tri nguyen
NT
Những câu hỏi liên quan
1) Cho bieu thuc A=\(3+\frac{2}{x-1}\). Tinh gia tri cua bieu thuc A khi |2x-3|=1
2) Rut gon bieu thuc B=\(\frac{x}{x-1}\)-\(\frac{x-5}{x+1}\)-\(\frac{3-x}{1-x^2}\)
3) Tim cac gia tri nguyen cua x de bieu thuc \(\frac{B}{A}\)co gia tri nguyen duong
1. Cho bieu thuc Afrac{-4}{n-1}(voi ninZ)a. So nguyen n phai co dieu Kien gi de A la Phan sob. Tin cac so nguyen n de A co gia tri nguyen2. Cho Phan so B frac{n}{n-4}(voi ninZ)a. Tim cac so Nguyen n de B la phan sob. Tim tat ca cac so nguyen n de B co gia tri nguyen3. Chung minh rang cac Phan so sau Co gia tri la so tu nhiena. frac{10^{2016}+2}{3}b.frac{10^{2016}+8}{9}
Đọc tiếp
1. Cho bieu thuc A=\(\frac{-4}{n-1}\)(voi n\(\in\)Z)
a. So nguyen n phai co dieu Kien gi de A la Phan so
b. Tin cac so nguyen n de A co gia tri nguyen
2. Cho Phan so B= \(\frac{n}{n-4}\)(voi n\(\in\)Z)
a. Tim cac so Nguyen n de B la phan so
b. Tim tat ca cac so nguyen n de B co gia tri nguyen
3. Chung minh rang cac Phan so sau Co gia tri la so tu nhien
a. \(\frac{10^{2016}+2}{3}\)
b.\(\frac{10^{2016}+8}{9}\)
3.a) tổng các cs của tử là 3 nên chia hết cho 3
b) tổng các cs của rử là 9 nên chia hết cho 9
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1) Cho bieu thuc: \(B=\left(\frac{\sqrt{x}}{\sqrt{x}+4}+\frac{4}{\sqrt{x}-4}\right):\frac{x+16}{\sqrt{x}+2}\left(x\ge0,x\ne16\right)\)
a) Cho bieu thuc A= \(\frac{\sqrt{x}+4}{\sqrt{x}+2}\) ; voi cac cua bieu thuc A va B da cho, hay tim cac gia tri cua x nguyen de gia tri cua bieu thuc B(A;-1) la so nguyen
so cap so nguyen duong (x,y) de p nhan gia tri so nguyên P=\(\frac{3x+3y+5}{x+y}\)
Tim so tu nhien n de phan so A=\(\frac{2n+1}{n-3}+\frac{3n-5}{n-3}-\frac{4n-5}{n-3}\)
a/Tim n de A nhan gia tri nguyen
b/Tim n de A la phan so toi gian
cho 2 bieu thuc:
\(A=\frac{3}{2-x}-\frac{3}{x+2}+\frac{3x^2}{x^2-4}\) va \(B=\frac{x+1}{x+2}\)
a.Rut gon A
b.tim gia tri nguyen cua x de P=A:B co gia tri nguyen
\(A=\frac{3}{2-x}+\frac{3}{x+2}+\frac{3x^2}{x^2-4}\)
\(A=\frac{-3}{x-2}+\frac{3}{x+2}+\frac{3x^2}{\left(x+2\right)\left(x-2\right)}\)
\(A=\frac{-3\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}+\frac{3\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}+\frac{3x^2}{\left(x-2\right)\left(x+2\right)}\)
\(A=\frac{-3x-6+3x-6+3x^2}{\left(x-2\right)\left(x+2\right)}\)
\(A=\frac{-12+3x^2}{\left(x-2\right)\left(x+2\right)}=\frac{3\left(-4+x^2\right)}{\left(x-2\right)\left(x+2\right)}=\frac{3\left(x-2\right)\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}\)
\(A=3\)
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\(a,A=\frac{3}{2-x}-\frac{3}{x+2}+\frac{3x^2}{x^2-4}\)
\(=\frac{-3\left(x+2\right)-3\left(x-2\right)+3x^2}{\left(x-2\right)\left(x+2\right)}\)
\(=\frac{-3x-6-3x+6+3x^2}{\left(x-2\right)\left(x+2\right)}\)
\(=\frac{3x^2-6x}{\left(x-2\right)\left(x+2\right)}\)
\(=\frac{3x\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}\)
\(=\frac{3x}{x+2}\)
\(b,ĐKXĐ:\hept{\begin{cases}x-2\ne0\\x+2\ne0\\x+1\ne0\end{cases}\Leftrightarrow\hept{\begin{cases}x\ne\pm2\\x\ne-1\end{cases}}}\)
Ta có : \(P=A:B=\frac{3x}{x+2}:\frac{x+1}{x+2}\)
\(=\frac{3x}{x+2}.\frac{x+2}{x+1}\)
\(=\frac{3x}{x+1}\)
\(=\frac{3x+3}{x+1}-\frac{3}{x+1}\)
\(=3-\frac{3}{x+1}\)
Để P nguyên thì \(3-\frac{3}{x+1}\inℤ\)
\(\Leftrightarrow\frac{3}{x+1}\inℤ\)
Vì \(x\inℤ\Rightarrow x+1\inℤ\)
Ta có bảng :
| x + 1 | -3 | -1 | 1 | 3 |
| x | -4 | -2 | 0 | 2 |
Vậy \(x\in\left\{-4;-2;0;2\right\}\)
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Cho bthuc: \(A=\frac{1}{2\sqrt{x}-2}-\frac{1}{2\sqrt{x}+2}+\frac{\sqrt{x}}{1-x}\)
a) Rut gon A
b) Tim gia tri cua x de /A/ =\(\frac{1}{2}\)
c) Tim x nguyen de A co gia tri nguyen
Tim x nguyen de phan so sau co gia tri nguyen
a) \(\frac{x^2-6x-3}{x-4}\) b) \(\frac{x^2-x+1}{x+2}\)
Cho bieu thuc \(A=\left(\frac{x+1}{x-1}-\frac{x-1}{x+1}+\frac{x^2-4x-1}{x^2-1}\right).\frac{x+2016}{x}\)
a, Voi gia tri nguyen nao cua x thi bieu thuc A co gia tri nguyen
b,Voi gia tri nao cua x thi A co gia tri duong