cai duoi mau la 2 chu kko phai x dau nha , mik viet nhanh nen danh nham mong ban thong cam
Theo de bai ta co \(\frac{a}{b}=\frac{3}{4}=>\frac{a}{3}=\frac{b}{4}\left(1\right)\) va \(\frac{b}{c}=\frac{4}{7}=>\frac{b}{4}=\frac{c}{7}\left(2\right)\)
Tu (1) va (2) suy ra \(\frac{a}{3}=\frac{b}{4}=\frac{c}{7}=\frac{c-a}{7-3}=\frac{28}{4}=7\) (AP DUNG TINH CHAT DAY TI SO BANG NHAU)
Suy ra a= 7.3=21 , b=7.4=28 , c=7.7=49
Vay a= 21 , b=28,c=49
Chuc ban hoc tot
Ta có :\(\frac{a}{b}=\frac{3}{4};\frac{b}{c}=\frac{4}{7}\)
\(\Rightarrow\) \(\frac{a}{3}=\frac{b}{4};\frac{b}{4}=\frac{c}{7}\)
\(\Rightarrow\) \(\frac{a}{3}=\frac{b}{4}=\frac{c}{7}\)
Áp dụng tính chất dãy tỉ số bằng nhau
\(\Rightarrow\)\(\frac{c}{7}=\frac{a}{3}=\frac{c-a}{7-3}=\frac{28}{4}=7\)
Suy ra \(\hept{\begin{cases}\frac{a}{3}=7\Leftrightarrow a=21\\\frac{b}{4}=7\Leftrightarrow b=28\\\frac{c}{7}=7\Leftrightarrow c=49\end{cases}}\)
Vậy ...
Cbht
a = 21; b = 28; c = 49
