Theo đề ta có:\(a=n^2=153k,1000\le n^2\le9999\)
\(\Leftrightarrow1000\le153k\le9999\)
\(\Rightarrow\frac{1000}{153}\le\frac{153k}{153}\le\frac{9999}{153}\approx6,5\le k\le65,3\)
Thử k= 7;8;9;...;65. Ta thấy: 153.17=\(51^2=2601\)
Vậy số chính phương có 4 chữ số chia hết cho 153 la 2601
tim a sao cho a la so chinh phuong va a chia het cho 153
cho x, y la cac so nguyen duong sao cho A = x^4 + y^4 / 15 cung la so nguyen duong . cmr : x va y deu chia het cho 3 va 5 , tu do tim gtnn cua A
a,ve do thi ham so y=3x
b,tim toa do diem A , biet A thuoc do thi ham so tren va A co tung do la 6
c,tim diem tren do thi sao cho diem do co tung do va hoanh do bang nhau
choS= abc +bca +cab . chung minh S k phai la so chinh phuong
mot don vi lam duong luc dau dat ke hoach giao cho 3 doi I, II, IIImoi doi lam 1 doan duong co chieu dai ti le (thuan )voi 7,8,9. nhung ve sau do thiet bi may moc va nhan luc cua doi thay doi nen ke hoach da duoc dieu chinh , moi doi lam mot doan duong ti le thuan voi 6,7,8. nhu vay doi IIIphai lam hon so voi ke hoach ban dau la 0,5 km duong . tinh chieu dai doan duong ma moi doi phai lam theo ke hoach moi
1.ba nha kinh doanh hun von theo ti le 2:3:4tinh so tien lai moi nguoi bik so tien lai dc chia theo ti le hun von tong so tien lai 180 trieu dong
2.bik cu 100kg thoc thi cho 60 kg gao. Hoi 20 bao thoc moi bao nang 60 kg thi cho bn kg gao ??
3.de dao con muong can 30 nguoi lm trog 8 h . neu tang them 10 thoi gian giam dc may h? (nang suat =nhau)
4. 2 xe o to tu A den B. van toc xe I la 60km/h. Van toc xe thu 2 la 40km/h. thoi gian xe I di it hon xe2 la 30 phut. Tinh thoi gian moi xe di tu A den B va chieu dai quang duong AB ?
5.ba doi may cay lm viec tren 3 canh dong co DT = nhau. Doi I hoan thanh cong viec trong 4 ngay, doi 2 trong 6 ngay , doi 3 trong 8 ngay. hoi moi doi co bn may( co cung nang suat)bik rang doi I nhieu hon doi 2 la 2 may?
6. cho ham so y=-2x
a. bik diem A(3:yo)thuoc dthi ham so y=-2x. tinh y mu 0
b. diemB(1,15:3) va C(1,5;-3) co thuoc dthi ham so y=-2x hay ko???
c.e do thi ham so y=-2x
Cho tam giac ABC nhon .Ve ve phia ngoai tam giac ABC cac tam giac deu ABD va ACE . Goi M la giao diem cua DC va BE.Chung minh rang.
a, Tam giac ABE bang tam giac ADC.
b, Tinh goc BMC.
tim phan so co mau khac 1 biet rang tich cua tu va mau la 210 va no co the viet duoc duoi dang so thap phan huu han, co ..................... phan so thoa man
6.a) tim 2 so x, ybik 7x=2y va x-y=16
b)so sanh a,b,c bik a/b=b/c=c/a
c)tim cac so a,b,cbik a/2=b/3=c/4 va a+2b-c=-20
d)cho x/2=y/5=z/7 tinh gia tri bieu thuc A=x-y+z/x+2y-z
e)cho 3x-2y/4=2z-4x/3=4y-3z/2.CMR x/2=y/3=z/4
f)cho a,b,c la cac so huu ti khac sao choa+b-c/c=a-b+c/b=-a+b+c/a
tinh gia tri bang so cua 1 bieu thuc m=(a+b)(b+c)(c+a)/abc
g)cho x/a=y/b=z/c CMRbz-cy/a=cx-az/b=ay-bx/c