\(M=\dfrac{a+5}{a-4}=\dfrac{a-4+9}{a-4}\)
=>\(M=\dfrac{a-4}{a-4}+\dfrac{9}{a-4}\)
=>\(M=1+\dfrac{9}{a-4}\)
M nhận giá trị nguyên khi \(\dfrac{9}{a-4}\)nhận giá trị nguyên
=> 9 \(⋮\) a - 4
=> a - 4 \(\in\)Ư(9)
=>Ư(9)\(\in\){\(\pm1;\pm3;\pm9\)}
ta có bảng giá trị
| a - 4 | 1 | -1 | 3 | -3 | 9 | -9 |
| a | 5 | 3 | 7 | 1 | 13 | -5 |
=> a \(\in\){5;3;7;1;13;-5}
cho mình 1 đúng nha
bai 1
cho bieu thuc A = 5/n+1 voi N THUOC Z
a, de A la phan so thi n co dieu kien gi ?
b , tim tat ca cac gia tri nguyen cua n de gia tri A la 1 so nguyen ?
bai 2
cho bieu thuc M = 6/n-3 voi n thuoc Z .Co bao nhieu gia tri cua n de :
a, M ko phai la phan so
b , M la phan so va cp gia tri nguyen ?
bai 3 viet tap hop cacs so nguyen sao cho :
-12/4 < x <6/3
A, Tim so tu nhien y de phan so 12/y co gia tri = 4
B, tim so tu nhien a de 3 phan so 21/a ; 22/a-1 ; 24/a+1 deu la so nguyen
tim cac gia tri nguyen cua n de phan so A=3.n+2/n-1 co gia tri la so nguyen
tim so tu nhien n de B=\(\dfrac{7n-8}{2n-3}\)
a) co gia tri lon nhat
b)co gia tri la so tu nhien
Voi gia tri nao cua x thuoc Z cac phan so sau co gia tri la 1 so nguyen
d, D=\(\dfrac{x^2-1}{x+1}\) e, E=\(\dfrac{n+2}{n-5}\)
voi gia tri nao cua x thuoc Z cac phan so sau co gia tri la 1 so nguyen
d.D= \(\dfrac{x^2-1}{x+1}\)
chung minh cac ps sau day la toi gian
b, \(\dfrac{n-1}{n-2}\)
tim n de phan so sau la toi gian :
a, \(\dfrac{-3}{5-n}\) b,\(\dfrac{3n+2}{5n+3}\)
a, tim tat ca cac so nguyen to p sao cho p+11 cung la so nguyen to
b,tim tat ca cac so nguyen to p de p+8,p+10 cung la cac so nguyen to
Bai1.Tim cac p/s bang p/s 34/51 va co mau la so tu nhien <16
Bai 2.Tim n thuoc z de 5/n-4la 1 so nguyen.
