tim cac so tu nhien a,b,c sao cho \(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=\frac{4}{5}\)
tim tat ca cac so tu nhien a, b, c khac 0 va khac nhau sao cho:
\(\frac{1}{a}\) +\(\frac{1}{b}\) +\(\frac{1}{c}\) =1
tim cac so tu nhien a,b(a khac 0) thoa man:
\(\frac{1}{a}-\frac{b}{6}=\frac{1}{3}\)
AI GIAI DUOC MINH CHO 30 TICK
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
1. Cho Phan so B=\(\frac{n}{n-4}\)(voi n \(\in\)Z)
a. Tim So nguyen n de B la Phan so
b. Tim so Nguyen n de B co Gia tri la so tu nhien
2. Tim cac so nguyen x, y biet
a.\(\frac{x}{-3}=\frac{4}{y}\)
b. \(\frac{2}{x}=\frac{y}{-9}\)
tim so tu nhien a va b sao cho \(\frac{5a+7b}{6a+5b}=\frac{29}{28}\)
tim phan so toi gian nho nhat co tu va mau la cac so tu nhien sao cho khi nhan phan so lan luot voi moi so \(\frac{10}{7};\frac{5}{6};\frac{15}{9}\)thi moi tich tim duoc la so tu nhien
CHO a,b,c thuoc N CMR :\(\frac{a}{a+b}+\frac{b}{b+c}+\frac{c}{a+c}\)la so tu nhien
Tim nEN
a)4n+6 chia het cho 3n-2
b)n2+2n+6 chia het cho n+4
c)\(\frac{3n+5}{n+1}\) la so tu nhien