truc can thuc o mau

\(\dfrac{26}{2\sqrt{3}+5}\)

CHO TAM GIAC ABC CAN TAI A VA DUONG CAO AD CO H LA TRUC TAM .TINH AD BIET AH=14CM, HB=HC=30CM

cho tam giac nhon abc nt duong tron tam (O;R) H la truc tam I,K lan luot la chan duong cao ke tu dinh A,B cua tam giac ABC(I thuoc BC,K thuoc AC). Goi M la trung diem cua BC Ke HJ Vuong goc voi AM (J thuoc AM)

CM AJK va ACM dong dang

giup minh vs......

1.Tim tat ca cac so nguyen n ( lnl <1000) sao cho can(3n^2 +789) la mot scphuong chia het cho 3.

2. Biet rang x la mot so thuc khac 0, tim gtnn cua bieu thuc: Q = ( 2011,2012x^2 -2x +2013,2014)/(2014,2015x^2)

viet cong thuc duong thang di qua diem S(-2;4),song song voi truc 0y 

nói cho mk cack tring bay nhé còn mk biết làm rùi 

truc can thuc va tinh

a) \(\frac{5}{4-\sqrt{11}}+\frac{1}{3+\sqrt{7}}-\frac{6}{\sqrt{7}-2}-\frac{\sqrt{7}-5}{2}\)

b) \(\frac{4}{\sqrt{5}-\sqrt{2}}+\frac{3}{\sqrt{5}-2}-\frac{2}{\sqrt{3}-2}+\frac{\sqrt{3}-1}{6}\)

• cho tam giac ABC(AC>AB).co AH la duong cao.lay M thuoc AH sao cho <ABM=<ACM.
• C/M M la truc tam

1 ba cu co 25000 dong. hoi ba co the mua duoc bao nhiu qua cam (so tien moi qua tim trong thuc te)

cho tam giac abc co truc tam h va a la mot duong cao biet ah/a'h=k chung minh tgB.tgC=1+k