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6 tháng 6 2017

\(0,3+\dfrac{-13}{2}+\dfrac{6}{5}\)

\(=\dfrac{3}{10}+\dfrac{-13}{2}+\dfrac{6}{5}\)

\(=-5\)

6 tháng 6 2017

0,3+\(\dfrac{-13}{2}+\dfrac{6}{5}\)

= \(\dfrac{3}{10}+\dfrac{-65}{10}+\dfrac{12}{10}\)

= \(\dfrac{-50}{10}\)=-5

24 tháng 12 2018

\(\dfrac{11}{15}.\dfrac{12}{13}+\dfrac{8}{15}+\dfrac{11}{15}.\dfrac{14}{13}\)

\(=\dfrac{11.12+11.14}{15.13}+\dfrac{8}{15}\)

\(=\dfrac{11.26}{15.13}+\dfrac{8}{15}\)

\(=\dfrac{11.2}{15}+\dfrac{8}{15}\)

\(=\dfrac{22+8}{15}\)

\(=2\)

29 tháng 11 2022

Sửa đề: \(\dfrac{4}{x+2}+\dfrac{2}{x-2}+\dfrac{5x-6}{4-x^2}\)

\(=\dfrac{4x-8+2x+4-5x+6}{\left(x-2\right)\left(x+2\right)}=\dfrac{x+2}{\left(x-2\right)\left(x+2\right)}=\dfrac{1}{x-2}\)

29 tháng 11 2022

\(=\dfrac{4x-8+2x+4-5x+6}{\left(x-2\right)\left(x+2\right)}=\dfrac{x+2}{\left(x-2\right)\left(x+2\right)}=\dfrac{1}{x-2}\)

20 tháng 12 2017

\(a,\dfrac{2^4.6^7}{9^3.4^6}=\dfrac{2^4.\left(2.3\right)^7}{\left(3^2\right)^3.\left(2^2\right)^6}=\dfrac{2^4.2^7.3^7}{3^6.2^{12}}=\dfrac{2^{11}.3^7}{3^6.2^{12}}=\dfrac{3}{2}\)

\(b,\dfrac{3^{18}.24^4}{9^4.81^5}=\dfrac{3^{18}.\left(3.2^3\right)^4}{\left(3^2\right)^4.\left(3^4\right)^5}=\dfrac{3^{18}.3^4.2^{12}}{3^8.3^{20}}=\dfrac{3^{22}.2^{12}}{3^{28}}=\dfrac{2^{12}}{3^8}\)

13 tháng 5 2018

B = ( \(\dfrac{5}{7}.0,6:3\dfrac{1}{2}\)) . ( 40% - 1,4) . \(\left(-2\right)^3\)

= (\(\dfrac{5}{7}.\dfrac{3}{5}\): \(\dfrac{7}{2}\)) . ( \(\dfrac{2}{5}-\dfrac{7}{5}\)) . (-8)

= (\(\dfrac{15}{35}:\dfrac{7}{2}\)) . \(\dfrac{-5}{5}\) . ( -8)

= (\(\dfrac{3}{7}.\dfrac{2}{7}\)) . (-1) . (-8)

= \(\dfrac{6}{49}\) . (-1) . (-8)

= \(\dfrac{-6}{49}\) . (-8)

= \(\dfrac{48}{49}\)

Vậy: B =\(\dfrac{48}{49}\)

Nhớ tick nha

13 tháng 5 2018

B=(\(\dfrac{3}{7}.\dfrac{2}{7}\)).(\(\dfrac{4}{10}-\dfrac{14}{10}\)).(-8)

B=\(\dfrac{3}{7}.\left(-1\right)\left(-8\right)\)

B=\(\dfrac{24}{7}\)

9 tháng 12 2018

\(\dfrac{18x}{x^3-9x}-\dfrac{2-x}{x+3}+\dfrac{3}{3-x}\)

=\(\dfrac{18x}{x\left(x^2-9\right)}-\dfrac{\left(2-x\right)\left(x-3\right)x}{\left(x+3\right)\left(x-3\right)x}-\dfrac{3x\left(x+3\right)}{\left(x-3\right)\left(x+3\right)x}\)

=\(\dfrac{18x-\left(2-x\right)\left(x-3\right)x-3x\left(x+3\right)}{x\left(x+3\right)\left(x-3\right)}\)

=\(\dfrac{18x-\left(2x-6-x^2+3x\right)x-3x^2-9x}{x\left(x+3\right)\left(x-3\right)}\)

=\(\dfrac{18x-2x^2+6x+x^3-3x^2-3x^2-9x}{x\left(x+3\right)\left(x-3\right)}\)

=\(\dfrac{x^3-8x^2+15x}{x\left(x-3\right)\left(x+3\right)}\)

=\(\dfrac{x\left(x^2-8x+15\right)}{x\left(x-3\right)\left(x+3\right)}\)

=\(\dfrac{x^2-3x-5x+15}{x\left(x-3\right)\left(x+3\right)}\)

=\(\dfrac{x\left(x-3\right)-5\left(x-3\right)}{\left(x-3\right)\left(x+3\right)}\)

=\(\dfrac{\left(x-3\right)\left(x-5\right)}{\left(x-3\right)\left(x+3\right)}\)

=\(\dfrac{\left(x-5\right)}{x+3}\)

8 tháng 12 2018

BẠN CŨNG CHƠI MINECRAFT AK

3 tháng 11 2018

\(\dfrac{17539}{8}\)

11 tháng 12 2017

\(a.\)

\(\left(x^2-25\right):\dfrac{2x+10}{3x-7}\)

\(=\left(x-5\right)\left(x+5\right).\dfrac{3x-7}{2\left(x+5\right)}\)

\(=\dfrac{\left(x-5\right)\left(x+5\right)\left(3x-7\right)}{2\left(x+5\right)}\)

\(=\dfrac{\left(x-5\right)\left(3x-7\right)}{2}\)

\(b.\)

\(\dfrac{x^2+x}{5x^2-10x+5}:\dfrac{3x+3}{5x-5}\)

\(=\dfrac{x\left(x+1\right)}{5\left(x^2-2x+1\right)}.\dfrac{5\left(x-1\right)}{3\left(x+3\right)}\)

\(=\dfrac{x\left(x+1\right)}{5\left(x-1\right)^2}.\dfrac{5\left(x-1\right)}{3\left(x+1\right)}\)

\(=\dfrac{x\left(x+1\right).5\left(x-1\right)}{5\left(x-1\right)^2.3\left(x+1\right)}\)

\(=\dfrac{x}{3\left(x-1\right)}\)

11 tháng 12 2017

\(\dfrac{x^2+x}{5x^2-10x+5}:\dfrac{3x+3}{5x-5}=\dfrac{5x\left(x+1\right)\left(x-1\right)}{15\left(x-1\right)^2\left(x+1\right)}=\dfrac{x}{3\left(x-1\right)}\)\(\left(x^2-25\right):\dfrac{2x+10}{3x-7}=\dfrac{\left(x-5\right)\left(x+5\right)\left(3x-7\right)}{2\left(x+5\right)}=\dfrac{\left(x-5\right)\left(3x-7\right)}{2}\)

4 tháng 12 2017

\(\dfrac{3x+1}{\left(x-1\right)^2}-\dfrac{1}{x+1}+\dfrac{x+3}{1-x^2}\)

\(=\dfrac{3x+1}{\left(x-1\right)\left(x+1\right)}-\dfrac{1}{x+1}+\dfrac{x+3}{1-x^2}\)

\(=\dfrac{3x+1}{\left(x-1\right)\left(x+1\right)}-\dfrac{1}{x+1}+\dfrac{-\left(x+3\right)}{\left(x+1\right)\left(x-1\right)}\)

\(=\dfrac{\left(3x+1\right)\left(x+1\right)}{\left(x-1\right)^2\left(x+1\right)}-\dfrac{\left(x-1\right)^2}{\left(x-1\right)^2\left(x+1\right)}+\dfrac{-\left(x+3\right)\left(x-1\right)}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{\left(3x+1\right)\left(x+1\right)-\left(x-1\right)^2-\left(x+3\right)\left(x-1\right)}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{3x^2+4x+1-\left(x^2-2x+1\right)-\left(x^2+2x+3\right)}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{x^2+4x+3}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{x^2+x+3x+3}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{x\left(x+1\right)+3\left(x+1\right)}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{\left(x+1\right)\left(x+1\right)}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{x+3}{\left(x-1\right)^2}\)

4 tháng 12 2017

\(\dfrac{3x+1}{\left(x-1\right)^2}-\dfrac{1}{x+1}+\dfrac{x+3}{1-x^2}\)

\(=\dfrac{\left(3x+1\right)\left(x+1\right)}{\left(x-1\right)^2\left(x+1\right)}-\dfrac{\left(x-1\right)^2}{\left(x-1\right)^2\left(x+1\right)}+\dfrac{-\left(x+3\right)\left(x-1\right)}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{3x^2+4x+1-x^2+2x-1-x^2-2x+3}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{x^2+4x+3}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{x^2+3x+x+3}{\left(x-1\right)^2\left(x+1\right)}\)

\(=\dfrac{\left(x+3\right)\left(x+1\right)}{\left(x-1\right)^2\left(x+1\right)}=\dfrac{x+3}{\left(x-1\right)^2}\)