\(x^2+7⋮x-2\Leftrightarrow\)\(\dfrac{x^2+7}{x-2}\in Z\Leftrightarrow\dfrac{x^2-4+11}{x-2}\in Z\Leftrightarrow x+2+\dfrac{11}{x-2}\in Z\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=1\\x-2=-1\\x-2=11\\x-2=-11\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\\x=13\\x=-9\end{matrix}\right.\)
Kl: x=3, x=1, x=13, x=-9
Tim x thuoc Z de A thuoc Z va tim gia tri do .
a/ A= x+3/x-2 .
b/ A= 1-2x/x+3 .
Cho ham so y=f(x) =12/x
c) tim x de y <0
d) tim x thuoc Z de y nhan GTLN
Cho don thuc A= -xy2 , B=5xy3z, C=5xy2
a, Tim cac so nguyen x de bieu thuc M= \(\dfrac{3}{7-x}\) dat gia tri lon nhat
tim gia tri nguyen cua x de bieu thuc:x^2+7/x+1 cung nhan gia tri la so nguyen
tim cac gia tri cua x de bieu thuc sau co gia tri bang 0:
P(x)=2x-7+(x-14)
Q(x)=x^2-64
tim cac gia tri cua x de bieu thuc sau co gia tri bang 0:
P(x)=2x-7+(x-14)
Q(x)=x^2-64
1 tim x
\(\dfrac{2}{3}+\dfrac{5}{7}.\left(\dfrac{7}{15}+x\right)=0\)
\(0,5.1\dfrac{1}{3}x-\left|-10.0,75\right|=\dfrac{17}{5}\)
2 tìm câc số x,y,z biết 7x=10y và x+y+z=514
tim x,y,z (cau a ) , tim x , y (cau b )
a, x : y : z = 3 : 4 : 5 va 5z2 - 3x2 - 2y2 = 594
b, z + y = x : y = 3.(x - y )
A=2004+\(\sqrt{2003-x}\)
a)Tim x de A co nghia
b)Tim x de A=2005
c)Tim GTNN cua A