a) ( 5x - 4)(4x + 6)=0

<=> \([^{5x-4=0}_{4x+6=0}< =>[^{x=\frac{4}{5}}_{x=\frac{-6}{4}}\)

Vậy S = \(\left\{\frac{4}{5};\frac{-6}{4}\right\}\)

b) ( 3,5x - 7 )( 2,1x - 6,3 ) = 0

<=> \([^{3,5x-7=0}_{2,1x-6,3=0}< =>[^{x=2}_{x=3}\)

Vậy S = \(\left\{2;3\right\}\)

c) ( 4x - 10 )( 24 + 5x ) = 0

<=> \([^{4x-10=0}_{24+5x=0}< =>[^{x=\frac{5}{2}}_{x=\frac{-24}{5}}\)

Vậy S = \(\left\{\frac{5}{2};\frac{-24}{5}\right\}\)

d) ( x - 3 )( 2x + 1 ) = 0

<=> \(\left[{}\begin{matrix}x-3=0\\2x+1=0\end{matrix}\right.< =>\left[{}\begin{matrix}x=3\\x=\frac{-1}{2}\end{matrix}\right.\)

Vậy S = \(\left\{3;\frac{-1}{2}\right\}\)

e) ( 5x - 10 )( 8 - 2x ) = 0

<=> \(\left[{}\begin{matrix}5x-10=0\\8-2x=0\end{matrix}\right.< =>\left[{}\begin{matrix}x=2\\x=4\end{matrix}\right.\)

Vậy S = \(\left\{2;4\right\}\)

f) ( 9 - 3x )( 15 + 3x ) = 0

<=> \(\left[{}\begin{matrix}9-3x=0\\15+3x=0\end{matrix}\right.< =>\left[{}\begin{matrix}x=3\\x=-5\end{matrix}\right.\)

Vậy S = \(\left\{3;-5\right\}\)

Học tốt nhaaa !

20) -5-(x + 3) = 2 - 5x ⇔ -5 - x - 3 = 2 -5x ⇔ 4x = 10 ⇔ x = \(\frac{5}{2}\)

Vậy...

1) 16 - 8x = 0 ⇔ 8(2 - x) = 0⇔ 2 - x = 0 ⇔ x = 2

Vậy phương trình có nghiệm là x = 2

\(a,3x-6=0\\ \Leftrightarrow x=2\\ b,\left(x+1\right)\left(2x+4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x+1=0\\2x+4=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-2\end{matrix}\right.\\ c,5x+3=2x+15\\ \Leftrightarrow5x-2x=15-3\\ \Leftrightarrow3x=12\\ \Leftrightarrow x=4\)

\(a.3x-6=0 \)   \(\Leftrightarrow 3x=6\)  \(\Leftrightarrow x=2\)

\(b.(x+1)(2x+4)=0 \)

\(x+1=0\)   Hay  \(2x+4=0\)

\(x=-1\)      Hay  \(x=-2\)

\(c.5x+3=2x+15\)

\(\Leftrightarrow 3x=12\)

\(\Leftrightarrow x=4\)

A. \(4\left(x+2\right)-7\left(2x-1\right)+9\left(3x-4\right)=30\)
\(\Leftrightarrow4x+8-14x+7+27x-36=30\)
\(\Leftrightarrow4x-14x+27x=30-8-7+36\)
\(\Leftrightarrow17x=51\)
\(\Leftrightarrow x=3\) . Vậy \(S=\left\{3\right\}\)

B. \(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)
\(\Leftrightarrow10x-16-12x+15=12x-16+11\)
\(\Leftrightarrow10x-12x-12x=16-15-16+11\)
\(\Leftrightarrow10x=-4\)
\(\Leftrightarrow x=-\dfrac{2}{5}\) . Vậy \(S=\left\{-\dfrac{2}{5}\right\}\)

Câu C) bạn xem lại đề nha mik tính ko đc

D. \(\left(5x-3\right)4x-2x\left(10x-3\right)=15\)
\(\Leftrightarrow20x^2-12x-20x^2+6x=15\)
\(\Leftrightarrow-6x=15\)
\(\Leftrightarrow x=-\dfrac{5}{2}\) . Vậy \(S=\left\{-\dfrac{5}{2}\right\}\)

1) \(\Rightarrow10x-16-12x+15=12x-16+11\)

\(\Rightarrow14x=4\Rightarrow x=\dfrac{2}{7}\)

2) \(\Rightarrow4x^2+4x+1-4x^2+13x-3-15=0\)

\(\Rightarrow17x=17\Rightarrow x=1\)

3) \(\Rightarrow\left(3x-1\right)\left(2x-7+6x-5\right)=0\)

\(\Rightarrow\left(2x-3\right)\left(3x-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)

2: Ta có: \(\left(2x+1\right)^2-\left(4x-1\right)\left(x-3\right)-15=0\)

\(\Leftrightarrow4x^2+4x+1-4x^2+12x+x-3-15=0\)

\(\Leftrightarrow17x=17\)

hay x=1

1) Ta có: 3x-12=5x(x-4)

\(\Leftrightarrow3x-12-5x\left(x-4\right)=0\)

\(\Leftrightarrow3x-12-5x^2+20x=0\)

\(\Leftrightarrow-5x^2+23x-12=0\)

\(\Leftrightarrow-5x^2+20x+3x-12=0\)

\(\Leftrightarrow\left(-5x^2+20x\right)+\left(3x-12\right)=0\)

\(\Leftrightarrow5x\left(-x+4\right)+3\left(x-4\right)=0\)

\(\Leftrightarrow5x\left(4-x\right)-3\left(4-x\right)=0\)

\(\Leftrightarrow\left(4-x\right)\left(5x-3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}4-x=0\\5x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\5x=3\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=\frac{3}{5}\end{matrix}\right.\)

Vậy: \(x\in\left\{4;\frac{3}{5}\right\}\)

2) Ta có: 3x-15=2x(x-5)

\(\Leftrightarrow3x-15-2x\left(x-5\right)=0\)

\(\Leftrightarrow3\left(x-5\right)-2x\left(x-5\right)=0\)

\(\Leftrightarrow\left(x-5\right)\left(3-2x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-5=0\\3-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\2x=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=\frac{3}{2}\end{matrix}\right.\)

Vậy: \(x\in\left\{5;\frac{3}{2}\right\}\)

3) Ta có: 3x(2x-3)+2(2x-3)=0

\(\Leftrightarrow\left(2x-3\right)\left(3x+2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-3=0\\3x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=3\\3x=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{3}{2}\\x=\frac{-2}{3}\end{matrix}\right.\)

Vậy: \(x\in\left\{\frac{3}{2};-\frac{2}{3}\right\}\)

4) Ta có: (4x-6)(3-3x)=0

\(\Leftrightarrow\left[{}\begin{matrix}4x-6=0\\3-3x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}4x=6\\3x=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{6}{4}=\frac{3}{2}\\x=1\end{matrix}\right.\)

Vậy: \(x\in\left\{\frac{3}{2};1\right\}\)

4) (4x - 6 ) ( 3 - 3x ) = 0

<=> \(\left[{}\begin{matrix}4x-6=0\\3-3x=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}4x=6\\3x=3\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x=\frac{3}{2}\\x=1\end{matrix}\right.\)

Bài 1 :

a, Ta có : \(3x-12=5x\left(x-4\right)\)

=> \(3x-12=5x^2-20x\)

=> \(3x-12-5x^2+20x=0\)

=> \(5x^2-23x+12=0\)

=> \(5x^2-20x-3x+12=0\)

=> \(5x\left(x-4\right)-3\left(x-4\right)=0\)

=> \(\left(5x-3\right)\left(x-4\right)=0\)

=> \(\left[{}\begin{matrix}5x-3=0\\x-4=0\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}x=\frac{3}{5}\\x=4\end{matrix}\right.\)

Vậy phương trình có nghiệm là x = \(\frac{3}{5}\) và x = 4 .

b, Ta có : \(3x-15=2x\left(x-5\right)\)

=> \(3x-15-2x\left(x-5\right)=0\)

=> \(3\left(x-5\right)-2x\left(x-5\right)=0\)

=> \(\left(3-2x\right)\left(x-5\right)=0\)

=> \(\left[{}\begin{matrix}3-2x=0\\x-5=0\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}x=\frac{3}{2}\\x=5\end{matrix}\right.\)

Vậy phương trình có nghiệm là x = \(\frac{3}{2}\) và x = 5 .

c, Ta có : \(3x\left(2x-3\right)+2\left(2x-3\right)=0\)

=> \(\left(3x+2\right)\left(2x-3\right)=0\)

=> \(\left[{}\begin{matrix}3x+2=0\\2x-3=0\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}3x=-2\\2x=3\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}x=-\frac{2}{3}\\x=\frac{3}{2}\end{matrix}\right.\)

Vậy phương trình có nghiệm là x = \(-\frac{2}{3}\) và x = \(\frac{3}{2}\) .

d, Ta có : \(\left(4x-6\right)\left(3-3x\right)=0\)

=> \(\left[{}\begin{matrix}4x-6=0\\3-3x=0\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}4x=6\\-3x=-3\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}x=\frac{6}{4}\\x=1\end{matrix}\right.\)

Vậy phương trình có nghiệm là x = 1 và x = \(\frac{6}{4}\) .