gia tri (x) :1 2 3 a 5 6 7 8 9 10
tan so(n) ;2 3 1 6 3 1 4 2 1 2 /N=25
biet so trung binh cong la 5,16 . tim a
giup minh voi
diem kiem tra 1 tiet mon toan cua 1 to hs dc ghi l o bang tan so sau
Diem(x) 5 6 9 10
tan so(n) 2 n 2 1
biet diem trung binh bang 6,8
le nha cac ban minh gap lam rui
so trung binh cong cua 6 so la 4. do them so thu 7 nen so trung binh cong cua 7 so la 5 . tim so thu 7
Gia tri(x) | 6 | 8 | 9 | 10 |
Tan so(n) | 5 | a | 3 | 1 |
tim a biet diem TBC bang 7,5
Cho Bt : n-3/n-5
a,Tinh gia tri cua A biet n = 6
b,So nguyen n phai co dieu kien gi de A la phan so ?
c, Tim n de A nhan gia tri nguyen
1,\(\frac{\frac{3}{3}-\frac{3}{5}+\frac{3}{11}+\frac{3}{13}}{\frac{7}{3}-\frac{7}{5}+\frac{5}{11}+\frac{5}{13}}\)
2,a,tim x biet:
a,\(\left(3x-2\right)^{10}=\left(3x-2\right)^6\) b\(\left(2x^2-13\right)^4=\left(-5\right)^4\)
3,tim so nguyen n de phan so sau co gia tri la 1 so nguyen va tinh gia tri do
a,A=\(\frac{3n+9}{n-4}\) b,B=\(\frac{6n+5}{2n-1}\)
AI LAM DC BAI NAO THI GIUP MK VS A MAI PHAI NOP ROI
cau 1:tinh gia tri bieu thuc
3/4 +1/1/4 *2/2/3-(-1/2)^2:6/5
cho ma co 2 dau/la hon so,con 1 dau la phan so,con ^2 la mu 2
cau 2:tim x biet
( x-1)^5= -32
cho ^5 co nghia la mu 5
bai 1 tim cac stn x y z sao cho x+y+z=xyz
bai 2cmr neu m^2+mn+n^2chia het cho 9 voi m ,n la cac stn thi m,n chia het cho 3
bai 3 tim stn n nho nhat de cac phan so sau toi gian
7/n+9.8/n+10,...,31/n+33
bai 4chung to rang phan so m^3+2m/m^4+3m^2 +1 toi gian
bai 5 a,cmr khong ton tai so chinh phuong nao co dang abab
b,cho 51 so nguyen duong khong vuot qua 100 cmr ton tai 2 so trong 51 so noi tren ma 1 so chia het cho so con lai
c,tim cac so co 3 chu so sao cho hieu cua so ay va gom 3 chu so ay viet theo thu tu nguoc lai la mot so chinh phuong
bai 6cmr A=2x(x+y-1)+y^2+1 luon nhan gia tri khong am voi moi x,y
bai 7 tim hai so nguyen duong sao cho tong ,hieu thuong (so lon chia cho so nho )cua chung cong lai duoc 38
bai 8 cho ba so a,b,c thoa man a/2009=b/2010=c/2011
tinh gia tri cua bieu thuc M=4(a-b)(b-c)-(c-a)^2
Cho so nguyen to n co 2 chu so hang chuc la x, hang don vi la y. Biet M=n/x+y. Tim n de M=2. Tim n de M dat gia tri nho nhat