\(-\frac{2087}{\frac{612}{10}}=-2087:\frac{612}{10}=-\frac{2087.10}{612}=-\frac{10435}{306}\)

mình trả lời bài tìm x cho bạn nha

BCNN(5,2) =10

=)) x/20=y/10;y/10=z/15

=))x/20=y/10=z/15

x/20=y/10=z/15=2x/40=3y/30=4z/12

áp dụng dãy tính chất tỉ số bằng nhau ta có

2x/40=3y/30=4z/12=2x-3y+4z/40-30+12=330/22=15

x/20=15=))x=300

y/10=15=))y=150

z/15=15=))z=225

vậy x=300;y=150;z=225

Trả lời :

\(\frac{2010}{1020}=\frac{2010:30}{1020:30}=\frac{67}{34}\)

~ Hok tốt ~

2010 / 1020 = 67 / 34

~ Học tốt ~

Đây là phân số tối gian rồi bạn ơi. Không đổi thành phân số hập phân đk vì số lớn.

NHớ k đúng cho mình nha.

\(\frac{-2087}{612}=-3\frac{251}{612}\)

\(\frac{17}{12}\)

1224/216 , tự rút gọn

\(a,cos\left(\dfrac{21\pi}{6}\right)=cos\left(3\pi+\dfrac{\pi}{2}\right)=cos\left(\pi+\dfrac{\pi}{2}\right)=-cos\left(\dfrac{\pi}{2}\right)=0\\ b,sin\left(\dfrac{129\pi}{4}\right)=sin\left(32\pi+\dfrac{\pi}{4}\right)=sin\left(\dfrac{\pi}{4}\right)=\dfrac{\sqrt{2}}{2}\\ c,tan\left(1020^o\right)=tan\left(5\cdot180^o+120^o\right)=tan\left(120^o\right)=-\sqrt{3}\)

a, \(\frac{2020.125+1000}{126.2020-1020}=\frac{2020.125+1000}{2020.125+2020-1020}=1\)

b,\(\left(\frac{1}{11.13}+\frac{1}{13.15}+...+\frac{1}{19.21}\right).426+x=19\)

\(< =>\left(\frac{1}{11}-\frac{1}{21}\right).213+x=19\)

\(< =>\frac{2130}{231}+x=19\)

\(< =>x=19-\frac{2130}{231}=...\)

a)\(\frac{2020\cdot125+1000}{126\cdot2020-1020}=\frac{2020\cdot125+1000}{2020\cdot125+2020-1020}=\frac{2020\cdot125+1000}{2020\cdot125+1000}=1\)

b) \(\left(\frac{1}{11\cdot13}+\frac{1}{13\cdot15}+\frac{1}{15\cdot17}+\frac{1}{17\cdot19}+\frac{1}{19\cdot21}\right)\cdot426+x=19\)

\(\Leftrightarrow\frac{1}{2}\left(\frac{2}{11\cdot13}+\frac{2}{13\cdot15}+\frac{2}{15\cdot17}+\frac{2}{17\cdot19}+\frac{2}{19\cdot21}\right)\cdot426+x=19\)

\(\Leftrightarrow\frac{1}{2}\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+\frac{1}{15}-\frac{1}{17}+\frac{1}{17}-\frac{1}{19}+\frac{1}{19}-\frac{1}{21}\right)\cdot426+x=19\)

\(\Leftrightarrow\frac{1}{2}\left(\frac{1}{11}-\frac{1}{21}\right)\cdot426+x=19\)

\(\Leftrightarrow\frac{1}{2}\cdot\frac{10}{231}\cdot426+x=19\)

\(\Leftrightarrow\frac{710}{77}+x=19\)

\(\Leftrightarrow x=19-\frac{710}{77}=\frac{753}{77}\)