3/2x + 5/3x + x = -69
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T
3
1 tháng 9 2020
\(a,5x-5^2=3x+25\)
\(5x-3x=25+5^2\)
\(2x=50\)
\(x=50:2\)
\(x=25\)
\(b,3x+69:23=2x-108:36\)
\(3x+3=2x-3\)
\(3x-2x=-3-3\)
\(x=-6\)
Học tốt
VD
0
23 tháng 11 2015
123 -5 . (x + 4) = 38
5 . (x + 4) = 123 - 38 = 85
x + 4 = 85 : 5 = 17
x = 17 - 4 = 13
(3x - 24) . 73 = 2.74
(3x - 24) = 2.7 = 14
3x - 16 = 14
3x = 14 + 16 = 30
x = 30 : 3 = 10
25 tháng 5 2022
Bài 2:
b: \(\left(2x+3\right)\left(x-4\right)+\left(x-5\right)\left(x-2\right)=\left(3x-5\right)\left(x-4\right)\)
\(\Leftrightarrow2x^2-8x+3x-12+x^2-7x+10=3x^2-12x-5x+20\)
\(\Leftrightarrow3x^2-12x-2=3x^2-17x+20\)
=>-12x-2=-17x+20
=>5x=22
hay x=22/5
c: \(\left(8x-3\right)\left(3x+2\right)-\left(4x+7\right)\left(x+4\right)=\left(2x+1\right)\left(5x-1\right)\)
\(\Leftrightarrow24x^2+16x-9x-6-\left(4x^2+16x+7x+28\right)=10x^2-2x+5x-1\)
\(\Leftrightarrow24x^2+7x-6-4x^2-23x-28=10x^2+3x-1\)
\(\Leftrightarrow20x^2-16x-34=10x^2+3x-1\)
\(\Leftrightarrow10x^2-19x-33=0\)
\(\text{Δ}=\left(-19\right)^2-4\cdot10\cdot\left(-33\right)=1681>0\)
Do đó: Phương trình có hai nghiệm phân biệt là:
\(\left\{{}\begin{matrix}x_1=\dfrac{19-41}{20}=\dfrac{-22}{20}=\dfrac{-11}{10}\\x_2=\dfrac{19+41}{20}=3\end{matrix}\right.\)
18 tháng 8 2017
Bài 2:
b)\((2x+3)(x-4)+(x-5)(x-2)=(3x-5)(x-4)\)
\(\Leftrightarrow2x^2-5x-12+x^2-7x+10=3x^2-17x+20\)
\(\Leftrightarrow3x^2-12x-2=3x^2-17x+20\)
\(\Leftrightarrow5x=22\Rightarrow x=\frac{22}{5}\)
c)\((8x-3)(3x+2)-(4x+7)(x+4)=(2x+1)(5x-1)\)
\(\Leftrightarrow24x^2+7x-6-4x^2-23x-28=10x^2+3x-1\)
\(\Leftrightarrow20x^2-16x-34=10x^2+3x-1\)
\(\Leftrightarrow10x^2-19x-33=0\)
\(\Leftrightarrow\left(x-3\right)\left(10x+11\right)=0\)
Suy ra x=3;x=-11/10
S
14 tháng 1 2019
a. \(\dfrac{6x+5}{2}-\dfrac{10x+3}{4}=2x+\dfrac{2x+1}{2}\)
\(\Leftrightarrow2\left(6x+5\right)-10x-3=8x+2\left(2x+1\right)\)
\(\Leftrightarrow12x+10-10x-3=8x+4x+2\)
\(\Leftrightarrow12x-10x-8x-4x=2-10+3\)
\(\Leftrightarrow-10x=-5\Leftrightarrow x=\dfrac{1}{2}\)
b. \(\left(x+1\right)^3-\left(x-1\right)^3=6\left(x^2+x+1\right)\)
\(\Leftrightarrow x^3+3x^2+3x+1-x^3+3x^2-3x+1=6x^2+6x+6\)
\(\Leftrightarrow6x^2+2=6x^2+6x+6\)
\(\Leftrightarrow6x^2-6x^2-6x=6-2\Leftrightarrow-6x=4\)
\(\Leftrightarrow x=\dfrac{-2}{3}\)
c. \(\dfrac{x+2}{13}+\dfrac{2x+45}{15}=\dfrac{3x+8}{37}+\dfrac{4x+69}{9}\)
\(\Leftrightarrow\left(\dfrac{x+2}{13}+1\right)+\left(\dfrac{2x+45}{15}-1\right)=\left(\dfrac{3x+8}{37}+1\right)+\left(\dfrac{4x+69}{9}-1\right)\)
\(\Leftrightarrow\dfrac{x+15}{13}+\dfrac{2\left(x+15\right)}{15}-\dfrac{3\left(x+15\right)}{37}-\dfrac{4\left(x+15\right)}{9}=0\)
\(\Leftrightarrow\left(x+15\right)\left(\dfrac{1}{13}+\dfrac{2}{15}-\dfrac{3}{37}-\dfrac{4}{9}\right)=0\)
Vì \(\left(\dfrac{1}{13}+\dfrac{2}{15}-\dfrac{3}{37}-\dfrac{4}{9}\right)>0\)
\(\Leftrightarrow x+15=0\Leftrightarrow x=-15\)
\(\dfrac{3}{2x}+\dfrac{5}{3x}+x=-69\left(x\ne0\right)\) đề như thế này phải không ạ
\(< =>\dfrac{9}{6x}+\dfrac{10}{6x}+\dfrac{6}{6x}=\dfrac{-414x}{6x}\)
suy ra
`<=>9+10+6=-414x`
`<=>-414x=25`
`<=>x=-25/414`
hay đề như thế này ạ
`3/2 x+5/3 x +x=-69`
`<=> x xx(3/2+5/3+1)=-69`
`<=> x xx 25/6=-69`
`<=> x =-69:25/6`
`<=>x=-414/25`