Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Ta có : \(\left(\frac{2}{11.13}+\frac{2}{13.15}+...+\frac{2}{19.21}\right)642-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
=> \(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+...+\frac{1}{19}-\frac{1}{21}\right)642-0,04:\left(x+1,05\right):0,12=19\)
=>
(nãy bấm nhầm) tiếp nà :
=> \(\left(\frac{1}{11}-\frac{1}{21}\right)462-0,04:\left(x+1,05\right):0,12=19\)
=> \(\frac{10}{231}.462-0,04:\left(x+1,05\right):0,12=19\)
=> \(20-0,04:\left(x+1,05\right):0,12=19\)
=> 0,04 : (x + 1,05) : 0,12 = 1
=> 0,04 : (x + 1,05) = 0,12
=> \(x+1,05=\frac{1}{3}\)
=> \(x=\frac{1}{3}-1,05=...\)
\(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-...+\frac{1}{19}-\frac{1}{21}\right).462-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)
\(\left(\frac{1}{11}-\frac{1}{21}\right).462-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)
\(\frac{10}{231}.462-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)
\(20-\left[2,04:\left(x+1,05\right)\right]:0,12=19\)
\(\left[2,04:\left(x+1,05\right)\right]:0,12=20-19=1\)
\(2,04:\left(x+1,05\right)=0,12\)
\(x+1,05=2,04:0,12\)
x+1,05=17
x=17-1,05=15,95
Tính cái ngoặc đầu trước rồi ráp lại sau nhé.
* \(\frac{2}{11.13}+\frac{2}{13.15}+...+\frac{2}{19.21}\)
\(=2\left(\frac{1}{11.13}+\frac{1}{13.15}+...+\frac{2}{19.21}\right)\)
\(=2\left(\frac{1}{11}-\frac{1}{21}\right)\)
\(=2.\frac{10}{231}\)
\(=\frac{20}{231}\)
Ta có: \(\frac{20}{231}.462-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
\(\Leftrightarrow40-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
\(\Leftrightarrow\left[0,04:\left(x+1,05\right)\right]:0,12=21\)
\(\Leftrightarrow0,04:\left(x+1,05\right)=2,52\)
\(\Leftrightarrow x+1,05=\frac{1}{63}\)
\(\Leftrightarrow x=-\frac{1303}{1260}\)
PS: Có những chỗ ra kết quả luôn, không tính vì mất thời gian. Nhưng bạn vẫn hiểu được đó, yên tâm.
Bài 1:
\(\Leftrightarrow\left(\dfrac{1}{11}-\dfrac{1}{21}\right)\cdot462-\left[2.04:\left(x+1.05\right)\right]:0.12=19\)
\(\Leftrightarrow\left[2.04:\left(x+1.05\right)\right]:0.12=1\)
\(\Leftrightarrow2.04:\left(x+1.05\right)=0.12\)
\(\Leftrightarrow x+1.05=17\)
hay x=15,85
\(\left(\frac{2}{11.13}+\frac{2}{13.15}+...+\frac{2}{19.21}\right).462-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
\(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+...+\frac{1}{19}-\frac{1}{21}\right).462-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
\(\left(\frac{1}{11}-\frac{1}{21}\right).462-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
\(\left(\frac{21}{231}-\frac{11}{231}\right).462-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
\(\frac{10}{231}.462-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
\(20-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
\(\left[0,04:\left(x+1,05\right)\right]:0,12=20-19\)
\(\left[0,04:\left(x+1,05\right)\right]:0,12=1\)
\(0,04:\left(x+1,05\right)=1.0,12\)
\(0,04:\left(x+1,05\right)=0,12\)
\(x+1,05=0,04:0,12\)
\(x+1,05=\frac{1}{3}\)
\(x=\frac{1}{3}-1,05\)
\(x=\frac{1}{3}-\frac{21}{20}\)
\(x=\frac{-43}{60}\)
Mk chưa kiểm tra lại đậu
Ban tính lại xem có đúng ko nhé
Nếu sai bảo mk
Tính????