Question

Cho tỉ lệ thức a/b=c/d, chứng minh: (a+2.c).(b+d)=(a+c) .(b+2.d)                        

Answer 1

Đặt \(\dfrac{a}{b}=\dfrac{c}{d}=k\)

=>a=bk; c=dk

(a+2c)(b+d)=(bk+2dk)(b+d)=k(b+2d)(b+d)

(a+c)(b+2d)=(bk+dk)(b+2d)=k(b+2d)(b+d)

Do đó: VT=VP(đpcm)