\(_{\frac{2}{3}\times_{\chi-\frac{1}{4}:\left(1\frac{1}{2}-\frac{3}{4}\right)=0,25\times\frac{3}{4}}}\)
tính :\(\left(1+\frac{1}{2}\right)\times\left(1+\frac{1}{3}\right)\times\left(1+\frac{1}{4}\right)\times_{......}\times\left(1+\frac{1}{98}\right)\times\left(1+\frac{1}{99}\right)\)
Ta đặt A = giá trị biểu thúc trên
A =3/2 * 4/3 * ....*99/98 *100/99
A = 100/2 =50
Vậy giá trị của biểu thức trên =50
Tính
A) \(\frac{15}{34}+\frac{7}{21}+\frac{19}{34}-1\frac{15}{17}+\frac{2}{3}\)
B) \(\left(-2\right)^3\times\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)
Tìm x
A) \(4\frac{1}{3}:\frac{\chi}{4}=6:0,3\)
B) \(\left(2^3:4\right)\times2^{\left(\chi+1\right)}=64\)
Tính:
b) \(\left(-2\right)^3.\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)
\(=\left(-2\right)^3.\left(\frac{3}{4}-\frac{1}{4}\right):\left(\frac{9}{4}-\frac{7}{6}\right)\)
\(=\left(-8\right).\frac{1}{2}:\frac{13}{12}\)
\(=\left(-4\right):\frac{13}{12}\)
\(=-\frac{48}{13}.\)
Tìm x
a) \(4\frac{1}{3}:\frac{x}{4}=6:0,3\)
⇒ \(\frac{13}{3}:\frac{x}{4}=20\)
⇒ \(\frac{x}{4}=\frac{13}{3}:20\)
⇒ \(\frac{x}{4}=\frac{13}{60}\)
⇒ \(x.60=4.13\)
⇒ \(x.60=52\)
⇒ \(x=52:60\)
⇒ \(x=\frac{13}{15}\)
Vậy \(x=\frac{13}{15}.\)
b) \(\left(2^3:4\right).2^{x+1}=64\)
⇒ \(\left(8:4\right).2^{x+1}=64\)
⇒ \(2.2^{x+1}=64\)
⇒ \(2^{x+1}=64:2\)
⇒ \(2^{x+1}=32\)
⇒ \(2^{x+1}=2^5\)
⇒ \(x+1=5\)
⇒ \(x=5-1\)
⇒ \(x=4\)
Vậy \(x=4.\)
Chúc bạn học tốt!
\(\left(-3\right)^3\times\left(\frac{5}{4}-0,25\right):\left(2\frac{1}{6}-1\frac{1}{9}\right)\)
mấy bia toán này dễ lắm
tính trong ngoặc trc ngoài ngoặc sau
rồi tính chung lại
tíc mình nha
Tìm tích:
1.\(\left(\frac{1}{2}+1\right)\times\left(\frac{1}{3}+1\right)\times\left(\frac{1}{4}+1\right)\times...\times\left(\frac{1}{999}+1\right)\)
2.\(\left(\frac{1}{2}-1\right)\times\left(\frac{1}{3}-1\right)\times\left(\frac{1}{4}-1\right)\times...\times\left(\frac{1}{1000}-1\right)\)
3.\(\frac{3}{2^2}\times\frac{8}{3^2}\times\frac{15}{4^2}\times...\times\frac{99}{10^2}\)
biết làm bài 1 thôi
\(\left(\frac{1}{2}+1\right)\times\left(\frac{1}{3}+1\right)\times\cdot\cdot\cdot\times\left(\frac{1}{999}+1\right)\)
= \(\frac{3}{2}\times\frac{4}{3}\times\frac{5}{4}\times\cdot\cdot\cdot\times\frac{1000}{999}\)
lượt bỏ đi còn :
\(\frac{1000}{2}=500\)
\(4\times\left(\frac{1}{4}\right)^2+25\times\left[\left(\frac{3}{4}\right)^3\div\left(\frac{5}{4}\right)^3\right]\div\left(\frac{3}{2}\right)^3\)
\(2^3+3\times\left(\frac{1}{2}\right)^0-1+\left[\left(-2\right)^2\div\frac{1}{2}\right]-8\)
\(4.\left(\frac{1}{4}\right)^2+25\left[\left(\frac{3}{4}\right)^3:\left(\frac{5}{4}\right)^3\right]:\left(\frac{3}{2}\right)^3=4.\frac{1}{16}+25\left(\frac{27}{64}.\frac{64}{125}\right).\frac{8}{27}\)
\(=\frac{1}{4}+25.\frac{27}{125}.\frac{8}{27}=\frac{1}{4}+\frac{8}{5}=\frac{37}{20}\)
\(2^3+3\left(\frac{1}{2}\right)^0-1+\left[\left(-2\right)^2:\frac{1}{2}\right]-8=8+3-1+4.2-8=10\)
Tính \(A=\left(0,25\right)^{-1}.\left(\frac{1}{4}\right)^{-2}.\left(\frac{4}{3}\right)^2.\left(\frac{5}{4}\right)^{-1}.\left(\frac{2}{3}\right)^{-3}\)
\(A=\left(0,25\right)^{-1}.\left(\frac{1}{4}\right)^{-2}.\left(\frac{4}{3}\right)^2.\left(\frac{5}{4}\right)^{-1}.\left(\frac{2}{3}\right)^{-3}\)
\(\Rightarrow A=4^1.4^2.\frac{16}{9}.\frac{4}{5}\frac{27}{8}\)
\(\Rightarrow A=\frac{64}{1}.\frac{16}{9}.\frac{4}{5}.\frac{27}{8}\)
\(\Rightarrow A=\frac{1536}{5}\)
Vậy \(A=\frac{1536}{5}\)
\(A=\left(1\frac{1}{6}\times\frac{6}{7}\times6:\frac{3}{5}\right):\left(4\frac{1}{5}\times\frac{10}{11}+5\frac{2}{10}\right)\)
\(B=1\frac{13}{15}\times25\%\times3+\left(\frac{8}{15}-\frac{79}{60}\right):1\frac{23}{4}\)
\(C=\frac{123}{4567}\times\frac{1}{8}+\frac{123}{4567}\times\frac{1}{2}-\frac{123}{4567}\times\frac{13}{8}\)
\(D=\frac{10\frac{1}{3}\times\left(24\frac{1}{2}-15\frac{6}{7}\right)-\frac{12}{11}\times\left(\frac{10}{3}-1,75\right)}{\left(\frac{5}{9}-0,25\right)\times\frac{60}{11}+194\frac{8}{99}}\)
\(25.\left(\frac{-1}{3}\right)^3+\frac{1}{5}-2.\left(\frac{-1}{2}\right)^2-\frac{1}{2}\)
\(\left(-2\right).\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)
câu thứ hai là (-2) mũ 3 nhé
\(25\cdot\left(-\frac{1}{3}\right)^3+\frac{1}{5}-2\cdot\left(-\frac{1}{2}\right)^2-\frac{1}{2}\)
\(=25\cdot\frac{-1}{27}+\frac{1}{5}-2\cdot\frac{\left(-1\right)^2}{2^2}-\frac{1}{2}\)
\(=\frac{-25}{27}+\frac{1}{5}-2\cdot\frac{1}{4}-\frac{1}{2}\)
\(=\frac{-98}{135}-\frac{1}{2}-\frac{1}{2}=\frac{-233}{135}\)
\(\left(-2\right)\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)
\(=\left(-2\right)\left(\frac{3}{4}-\frac{25}{100}\right):\left(\frac{9}{4}-\frac{7}{6}\right)\)
\(=\left(-2\right)\left(\frac{75}{100}-\frac{25}{100}\right):\left(\frac{27}{12}-\frac{14}{12}\right)\)
\(=\left(-2\right)\cdot\frac{50}{100}:\frac{13}{12}\)
\(=\left(-2\right)\cdot\frac{1}{2}:\frac{13}{12}\)
\(=-1\cdot\frac{12}{13}=-\frac{12}{13}\)
Sửa phần 2 : \(\left(-2\right)^3\cdot\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)
\(=\left(-8\right)\cdot\left(\frac{3}{4}-\frac{25}{100}\right):\left(\frac{9}{4}-\frac{7}{6}\right)\)
\(=\left(-8\right)\cdot\left(\frac{3}{4}-\frac{1}{4}\right):\left(\frac{27}{12}-\frac{14}{12}\right)\)
\(=\left(-8\right)\cdot\frac{1}{2}:\frac{13}{12}\)
\(=\left(-4\right):\frac{13}{12}=\frac{\left(-4\right)\cdot12}{13}=\frac{-48}{13}\)
\(4\frac{1}{3}\times\left(\frac{1}{2}-\frac{1}{6}\right)\le x\le-\frac{2}{3}\times\left(\frac{1}{3}-\frac{1}{2}-\frac{3}{4}\right)\)
gợi ý:
Bước 1: tính bên trái và bên phải của x
Bước 2:lập luận ra để bài khó thành cơ bản
Bước 3:bn chỉ cần ghi kết quả
chú ý: Bài này lớp 6 hk nhiều r mak
chúc thành công
\(4\frac{1}{3}(\frac{1}{2}-\frac{1}{6})\le x\le-\frac{2}{3}(\frac{1}{3}-\frac{1}{2}-\frac{3}{4})\)
\(\Rightarrow\frac{13}{9}\le\frac{x}{1}\le\frac{11}{18}\)
\(\Rightarrow\frac{26}{18}\le\frac{18x}{18}\le\frac{11}{18}\)
\(\Rightarrow26\le18x\le11\)
\(\Rightarrow x=1\)