la sao

cho \(\frac{2a+b}{a-2b}=\frac{2c+d}{c-2d}\)c/m rang \(\frac{a}{b}=\frac{c}{d}\)

Cho \(\frac{2a+b}{a-b}=\frac{2c+d}{c-d}\) c.m rang \(\frac{a}{b}=\frac{c}{d}\)

Cho x/y=4/5 và x+1,2/y=11/15

Tim x,y biet

a)\(\frac{x}{y}=\frac{4}{5},\frac{x+1,2}{y}=\frac{11}{15}\)

cho \(\Delta ABC\) có \(\widehat{A}>\widehat{B}\) _{là 90⁰ .Kẻ đường cao AH}

A)C/mrang \(\widehat{BAH}=\widehat{ACH}\)

b)c/m \(\Delta AHB=\Delta AHC\) va cs cacs gocs bangwf nhau

timGTLN cua B=(3x-2y)²-(4y-6x)²-/xy-24/