tim x biet
1/3x+2/5(x-1)=4
1/2-1/3:3x0-=5
tim stn nho nhat chia cho 5, cho 7, cho 9 co so du theo thu tu la 3;4;5
Tinh tong: 1-5/6+7/12-9/20+11/30-13/42+15/56-17/12+19/90
TIM x THUOC Z , BIET :
a) / 2x + 1 / = 7
b) 3/x + 1 / + 1 = 27
c) 20 = 20 + 19 + 18 + 17 + ..... + x
d) x + ( x+ 1 ) + ( x + 2 + ...... + 29 + 30 = 30
tim x biet :
a) 1/3 + 1/6 +1/10+ ...+ 2/ x*(x+1)
b) 1/2 + 1/6 +1/12 + ...+1/x=72/73
1) Tim x biet :
a) - 12 (x - 5) + 7 . (3 - x) = 5
b) 30 . (x + 2) - 6 . (x - 5) - 24x = 100
a) Tim x biet:
1/3 + 1/12 + 1/30 +...+ 2/x(x + 1) (x + 2)
b) Tinh:
(1 + 37) . (1 + 37/2) . (1 + 37/3)...(1 + 37/39)
(1 + 39) . (1 + 39/2) . (1 + 39/3)...(1 + 39/37)
Tim x biet : 20 . 2^x + 1 = 10.4^2 + 1
Tim x : ( 4-x:2)^3 - 1 = 2 . (2^3 - 5 : 2^0 )
Tìn x biết 1/2+1/6+1/12+1/20+1/30+1/42+1/x.(x+1)=3/8
tim x dua vao quan he uoc boi:
tim so tu nhien x sao cho x-1 la uoc cua 12
tim so tu nhien x sao cho 2x+1 la uoc cua 28
tim so tu nhien x sao cho x+15 la boi cua x+3
tim cac so nguyen x,y sao cho (x+1)(y-2)=3
tim so nguyen x sao cho(x+2).(y-1)=2
tim so nguyen to x vua la uoc cua 275 vua la uoc cua 180
tim so nguyen to x,y biet x+y=12 va UCLL (x:y)=5
tim so tu nhien x,y biet x+y=32 va UCLL (x:y)=8
tim so tu nhien x biet x chia het cho10; xchia het cho12; x chia het cho15 va 100<x<150
tim so x nho nhat khac 0b biet x chia het cho 24 va 30
40 chia het cho x . 56 chia het cho x va x>6
1 tim cac so nguyen x,y biet
x/7=6/21
-5/y=20/28
1/2=x/12
x/8=-28/32
3/y=12/24
3/4=15/y
2 viet 3 phan so bang phan so -10/15