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Giải phương trình:
\(\frac{x+1}{58}+\frac{x+2}{57}=\frac{x+3}{56}+\frac{x+4}{55}\)
\(\Leftrightarrow\left(\frac{x+1}{58}+1\right)+\left(\frac{x+2}{57}+1\right)=\left(\frac{x+3}{56}+1\right)+\left(\frac{x+4}{55}+1\right)\)
\(\Leftrightarrow\frac{x+59}{58}+\frac{x+59}{57}-\frac{x+59}{56}-\frac{x+59}{55}=0\)
\(\Leftrightarrow\left(x+59\right)\left(\frac{1}{58}+\frac{1}{57}-\frac{1}{56}-\frac{1}{55}\right)=0\)
\(\Leftrightarrow x+59=0\) \(\left(\frac{1}{58}+\frac{1}{57}-\frac{1}{56}-\frac{1}{55}\ne0\right)\)
\(\Leftrightarrow x=-59\)
Vậy : \(S=\left\{-59\right\}\)
\(\frac{x+1}{58}+\frac{x+2}{57}=\frac{x+3}{56}+\frac{x+4}{55}\)
\(\Leftrightarrow\) \(\frac{x+1}{58}+1+\frac{x+2}{57}+1=\frac{x+3}{56}+1+\frac{x+4}{55}+1\)
\(\Leftrightarrow\) \(\frac{x+59}{58}+\frac{x+59}{57}=\frac{x+59}{56}+\frac{x+59}{55}\)
\(\Leftrightarrow\) \(\frac{x+59}{58}+\frac{x+59}{57}-\frac{x+59}{56}-\frac{x+59}{55}=0\)
\(\Leftrightarrow\) (x + 59)(\(\frac{1}{58}+\frac{1}{57}-\frac{1}{56}-\frac{1}{55}\)) = 0
\(\Leftrightarrow\) x + 59 = 0
\(\Leftrightarrow\) x = -59
Vậy S = {-59}
Chúc bn học tốt!!
\(a,\frac{3}{-56}-\frac{-7}{64}=\frac{-3.8}{448}+\frac{7.7}{448}=\frac{25}{448}\)
\(b,\frac{-5}{54}-\frac{11}{-36}=-\frac{5}{54}+\frac{11}{36}=\frac{-5.2}{108}+\frac{3.11}{108}=\frac{23}{108}\)
\(c,\frac{9}{28}+\frac{-2}{29}=\frac{9.29-2.28}{812}=\frac{205}{812}\)
\(d,\frac{-5}{-72}+\frac{7}{-48}=\frac{5}{72}-\frac{7}{48}=\frac{5.2-7.3}{144}=-\frac{11}{144}\)
\(e,\frac{-5y}{2x^3}+\frac{2x}{3y}=\frac{-5y.3y+2x.2x^3}{6x^3y}=\frac{-15y^2+4x^4}{6x^3y}\)
\(f,\frac{2}{3x^4y^5}+\frac{5y^3}{2x^6}=\frac{2.2x^2+5y^3.3y^5}{6x^6y^5}=\frac{4x^2+15y^8}{6x^6y^5}\)
\(\frac{-1}{2}+\frac{1}{3}+\frac{2}{4}=\frac{-6}{12}+\frac{4}{12}+\frac{6}{12}\)
= \(\frac{4}{12}\)
\(\frac{x+3}{5}=\frac{y-2}{2}=\frac{z+1}{-9}\)
\(=\frac{5\left(x+3\right)+3\left(y-2\right)+\left(z+1\right)}{5.5+3.2-9}\)
\(=\frac{56+15-6+1}{22}=3\)
\(\Rightarrow x+y+z=3\left(5+2-9\right)-\left(3-2+1\right)=-8\)
\(2018^2-2017.2019\)
\(=2018^2-\left(2018-1\right)\left(2018+1\right)\)
\(=2018^2-\left(2018^2-1\right)=1\)
\(56^2+56.88+44^2\)
\(=56^2+2.56.44+44^2\)
\(=\left(56+44\right)^2\)
\(=100^2=10000\)
\(\frac{2018^3+1}{2018^2-2017}\)
\(=\frac{\left(2018+1\right)\left(2018^2-2018+1\right)}{2018^2-2017}\)
\(=\frac{2019\left(2018^2-2017\right)}{2018^2-2017}=2019\)
Chúc bạn học tốt.
Xin lỗi mình làm hơi tắt nha !!!Còn 1 cách nữa ,nếu bạn muốn thì nói với mình nha !!
Ta có : \(\frac{x-1}{59}+\frac{x-2}{58}+\frac{x-3}{57}=\frac{x-4}{56}+\frac{x-5}{55}+\frac{x-6}{54}\)
\(\Leftrightarrow\frac{x}{59}+\frac{x}{58}+\frac{x}{57}-\frac{x}{56}-\frac{x}{55}-\frac{x}{54}=\frac{1}{59}+\frac{2}{58}+\frac{3}{57}-\frac{4}{56}-\frac{5}{55}-\frac{6}{54}\)
<=> x = 60
Vậy x = 60
Bạn kiểm tra lại đề nhé. Chỗ
\(.....=\frac{x-4}{56}+\frac{x-5}{56}+\frac{x-6}{54}\)
\(\frac{1}{x^2+3x+2}+\frac{1}{x^2+5x+6}+...+\frac{1}{x^2+15x+56}=\frac{1}{14}\)
\(\Leftrightarrow\frac{1}{\left(x+1\right)\left(x+2\right)}+\frac{1}{\left(x+2\right)\left(x+3\right)}+...+\frac{1}{\left(x+7\right)\left(x+8\right)}=\frac{1}{14}\)
\(\Leftrightarrow\frac{1}{x+1}-\frac{1}{x+2}+\frac{1}{x+2}-\frac{1}{x+3}+...+\frac{1}{x+7}-\frac{1}{x+8}=\frac{1}{14}\)
\(\Leftrightarrow\frac{1}{x+1}-\frac{1}{x+8}=\frac{1}{14}\)
Làm nốt
2/
\(T=8x^2-4x+\frac{1}{4x^2}+15\)
\(=\left(4x^2-4x+1\right)+\left(4x^2+\frac{1}{4x^2}-2\right)+16\)
\(=\left(2x-1\right)^2+\left(\frac{4x^2-1}{2x}\right)^2+16\ge16\)