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Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời. \(\left(x^2-4\right)+\left(8-5.x\right).\left(x+2\right)+4.\left(x-2\right).\left(x+1\right)=0\) \(\Leftrightarrow x^2-4+8.x+16-5.x^2-10.x+\left(4.x-8\right).\left(x+1\right)=0\) \(\Leftrightarrow x^2-4+8.x+16-5.x^2-10.x+4.x^2+4.x-8.x-8=0\) \(\Leftrightarrow0+4-6.x=0\) \(\Leftrightarrow4-6.x=0\) \(\Leftrightarrow-6.x=-4\) \(\Rightarrow x=\frac{2}{3}\) Vậy x = \(\frac{2}{3}\) a) 3x - 2(5 + 2x) =45 - 2x => 3x - 10 - 4x = 45 - 2x => 3x - 4x + 2x = 45 + 10 => x = 55 b) \(\frac{x-3}{5}=6-\frac{1-2x}{3}\) => \(\frac{x-3}{5}=\frac{2x+17}{3}\) => 5(2x + 17) = 3(x - 3) => 10x + 85 = 3x - 9 => 7x = -94 => x = -94/7 c) \(\frac{5\left(x-1\right)+2}{6}-\frac{7x-1}{4}=\frac{2\left(2x+1\right)}{7}-5\) => \(\frac{5x-3}{6}-\frac{7x-1}{4}=\frac{4x-33}{7}\) => \(\frac{10x-6}{12}-\frac{21x-3}{12}=\frac{4x-33}{7}\) => \(\frac{-11x-3}{12}=\frac{4x-33}{7}\) => (-11x - 3).7 = (4x - 33).12 = -77x - 21 = 48x - 396 => x = 3 d) (x - 1)(5x + 3) = (3x - 8)(x - 1) => (x - 1)(5x + 3) - (3x - 8)(x -1) = 0 => (x - 1)(2x + 11) = 0 => \(\orbr{\begin{cases}x-1=0\\2x+11=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=1\\x=-5,5\end{cases}}\) e) (x - 1)(x2 + 5x - 2) - (x3 - 1) = 0 => (x - 1)(x2 + 5x - 2) - (x - 1)(x2 + x + 1) = 0 => (x - 1)(4x - 3) = 0 => \(\orbr{\begin{cases}x-1=0\\4x-3=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=1\\x=0,75\end{cases}}\) f) \(\frac{x-17}{33}+\frac{x-21}{29}+\frac{x}{25}=4\) => \(\left(\frac{x-17}{33}-1\right)+\left(\frac{x-21}{29}-1\right)+\left(\frac{x}{25}-2\right)=0\) => \(\frac{x-50}{33}+\frac{x-50}{29}+\frac{x-50}{25}=0\) => \(\left(x-50\right)\left(\frac{1}{33}+\frac{1}{29}+\frac{1}{25}\right)=0\) => x - 50 = 0 (Vì \(\frac{1}{33}+\frac{1}{29}+\frac{1}{25}\ne0\)) => x = 50 b, \(\frac{x-3}{5}=6-\frac{1-2x}{3}\) \(\Leftrightarrow\frac{x-3}{5}=\frac{17+2x}{3}\Leftrightarrow3x-9=85+10x\) \(\Leftrightarrow-7x=94\Leftrightarrow x=-\frac{94}{7}\) f, sửa : \(\frac{x+1}{65}+\frac{x+3}{63}=\frac{x+5}{61}+\frac{x+7}{59}\) \(\Leftrightarrow\frac{x+1}{65}+1+\frac{x+3}{63}+1=\frac{x+5}{61}+1+\frac{x+7}{59}+1\) \(\Leftrightarrow\frac{x+66}{65}+\frac{x+66}{63}=\frac{x+66}{61}+\frac{x+66}{59}\) \(\Leftrightarrow\frac{x+66}{65}+\frac{x+66}{63}-\frac{x+66}{61}-\frac{x+66}{59}=0\) \(\Leftrightarrow\left(x+66\right)\left(\frac{1}{65}+\frac{1}{63}-\frac{1}{61}-\frac{1}{59}\ne0\right)=0\) \(\Leftrightarrow x=-66\) a) \(\frac{x-5}{100}+\frac{x-4}{101}+\frac{x-3}{102}=\frac{x-100}{5}+\frac{x-101}{4}+\frac{x-102}{3}\) a) 7x - 35 = 0 <=> 7x = 0 + 35 <=> 7x = 35 <=> x = 5 b) 4x - x - 18 = 0 <=> 3x - 18 = 0 <=> 3x = 0 + 18 <=> 3x = 18 <=> x = 5 c) x - 6 = 8 - x <=> x - 6 + x = 8 <=> 2x - 6 = 8 <=> 2x = 8 + 6 <=> 2x = 14 <=> x = 7 d) 48 - 5x = 39 - 2x <=> 48 - 5x + 2x = 39 <=> 48 - 3x = 39 <=> -3x = 39 - 48 <=> -3x = -9 <=> x = 3
K
Khách
CM
Cao Minh Tâm
13 tháng 6 2019
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\(\Leftrightarrow\left(\frac{x-5}{100}-1\right)+\left(\frac{x-4}{101}-1\right)+\left(\frac{x-3}{102}-1\right)=\left(\frac{x-100}{5}-1\right)+\left(\frac{x-101}{4}-1\right)+\left(\frac{x-102}{3}-1\right)\)
\(\Leftrightarrow\frac{x-105}{100}+\frac{x-105}{101}+\frac{x-105}{102}=\frac{x-105}{5}+\frac{x-105}{4}+\frac{x-105}{3}\)
\(\Leftrightarrow\left(x-105\right)\left(\frac{1}{100}+\frac{1}{101}+\frac{1}{102}-\frac{1}{5}-\frac{1}{4}-\frac{1}{3}\right)=0\)
\(\Leftrightarrow x=105\)
b) \(\frac{29-x}{21}+\frac{27-x}{23}+\frac{25-x}{25}+\frac{23-x}{27}+\frac{21-x}{29}=-5\)
\(\Leftrightarrow\left(\frac{29-x}{21}+1\right)+\left(\frac{27-x}{23}+1\right)+\left(\frac{25-x}{25}+1\right)+\left(\frac{23-x}{27}+1\right)+\left(\frac{21-x}{29}+1\right)=0\)
\(\Leftrightarrow\frac{50-x}{21}+\frac{50-x}{23}+\frac{50-x}{25}+\frac{50-x}{27}+\frac{50-x}{29}=0\)
\(\Leftrightarrow\left(50-x\right)\left(\frac{1}{21}+\frac{1}{23}+\frac{1}{25}+\frac{1}{27}+\frac{1}{29}\right)=0\)
\(\Leftrightarrow x=50\)
24 tháng 3 2020
