\(\frac{64x^3+1}{16x^2-1}=\frac{A}{4x-1}\left(x\ne\pm\frac{1}{4}\right)\)

\(\Leftrightarrow\frac{\left(4x+1\right)\left(16x^2+4x+1\right)}{\left(4x+1\right)\left(4x-1\right)}=\frac{A}{4x-1}\)

\(\Leftrightarrow\frac{\left(16x^2+4x+1\right)}{\left(4x-1\right)}=\frac{A}{4x-1}\)

Vậy \(A=\left(16x^2+4x+1\right)\)

\(\frac{4x^2+3x-7}{B}=\frac{4x+7}{2x-3}\left(x\ne\frac{3}{2}\right)\)

\(\Leftrightarrow\frac{4x^2+7x-4x-7}{B}=\frac{4x+7}{2x-3}\)

\(\Leftrightarrow\frac{x\left(4x+7\right)-\left(4x+7\right)}{B}=\frac{4x+7}{2x-3}\)

\(\Leftrightarrow\frac{\left(x-1\right)\left(4x+7\right)}{B}=\frac{4x+7}{2x-3}\)

\(\Leftrightarrow\frac{\left(x-1\right)}{B}=\frac{1}{2x-3}\)

\(\Leftrightarrow B=\left(x-1\right)\left(2x-3\right)=2x^2-5x+3\)

a) \(\frac{6x-5}{-7}=\frac{5x-3}{-5}\)

=> -5(6x - 5) = -7(5x - 3)

=> -30x + 25 = -35x + 21

=> -30x + 25  + 35x - 21 = 0

=> (-30x + 35x) + (25 - 21) = 0

=> 5x + 4 = 0

=> 5x = -4

=> x = -4/5

b) \(\frac{12-7x}{-13}=\frac{4-3x}{-5}\)

=> -5(12 - 7x) = -13(4 - 3x)

=> -60 + 35x = -52 + 39x

=> -60 + 35x + 52 - 39x = 0

=> (-60 + 52) + (35x - 39x) = 0

=> -8 - 4x = 0

=> -8 = 4x

=> x = -2

c) \(\frac{2x+4}{7}=\frac{4x-2}{15}\)

=> 15(2x + 4) = 7(4x - 2)

=> 30x + 60 = 28x - 14

=> 30x + 60 - 28x + 14 = 0

=> 2x + 74 = 0

=> 2x = -74

=> x = -37

a) 4 ( x + 5 )( x + 6 )( x + 10 )( x + 12 ) = 3x²
Do x = 0 không là nghiệm pt nên chia 2 vế pt cho \(x^2\ne0\), ta được :

\(\frac{4}{x^2}\left(x^2+60+17x\right)\left(x^2+60+16x\right)=3\)

\(\Leftrightarrow4\left(x+\frac{60}{x}+17\right)\left(x+\frac{60}{x}+16\right)=3\)

Đến đây ta đặt  \(x+\frac{60}{x}+16=t\left(1\right)\)

Ta được :

\(4t\left(t+1\right)=3\Leftrightarrow4t^2+4t-3=0\Leftrightarrow\left(2t+3\right)\left(2t-1\right)=0\)

Từ đó ta lắp vào ( 1 ) tính được x 

này như thế này phải không

(4x²+4x-7x-7)(2x+3)= 4x(x+1)-7(x+1)= (4x-7)(x+1)

a: \(\Leftrightarrow4\left(x^2+60+17x\right)\left(x^2+60+16x\right)=3x^2\)

\(\Leftrightarrow4\cdot\left[\left(x^2+60\right)^2+33x\left(x^2+60\right)+272x^2\right]=3x^2\)

=>4(x^2+60)^2+132x(x^2+60)+1085x^2=0

=>4(x^2+60)^2+62x(x^2+60)+70x(x^2+60)+1085x^2=0

=>2(x^2+60)(2x^2+120+31x)+35x(2x^2+120+31x)=0

=>(2x^2+120+35x)(2x^2+31x+120)=0

=>\(x\in\left\{\dfrac{-35\pm\sqrt{265}}{4};-\dfrac{15}{2};-8\right\}\)

b: Đặt x^2-3x=a

Phương trình sẽ là \(\dfrac{1}{a+3}+\dfrac{2}{a+4}=\dfrac{6}{a+5}\)

\(\Leftrightarrow\dfrac{a+4+2a+6}{\left(a+3\right)\left(a+4\right)}=\dfrac{6}{a+5}\)

=>(3a+10)(a+5)=6(a^2+7a+12)

=>6a^2+42a+72=3a^2+15a+10a+50

=>3a^2+17a+22=0

=>x=-2 hoặc x=-11/3

\(\frac{4}{2x+3}-\frac{7}{3x-5}=0\left(đkxđ:x\ne-\frac{3}{2};\frac{5}{3}\right)\)

\(< =>\frac{4\left(3x-5\right)}{\left(2x+3\right)\left(3x-5\right)}-\frac{7\left(2x+3\right)}{\left(2x+3\right)\left(3x-5\right)}=0\)

\(< =>12x-20-14x-21=0\)

\(< =>2x+41=0< =>x=-\frac{41}{2}\left(tm\right)\)

\(\frac{4}{2x-3}+\frac{4x}{4x^2-9}=\frac{1}{2x+3}\left(đk:x\ne-\frac{3}{2};\frac{3}{2}\right)\)

\(< =>\frac{4\left(2x+3\right)}{\left(2x-3\right)\left(2x+3\right)}+\frac{4x}{\left(2x-3\right)\left(2x+3\right)}-\frac{2x-3}{\left(2x+3\right)\left(2x-3\right)}=0\)

\(< =>8x+12+4x-2x+3=0\)

\(< =>10x=15< =>x=\frac{15}{10}=\frac{3}{2}\left(ktm\right)\)

\(\frac{2}{2x+1}+\frac{x}{4x^2-1}=\frac{7}{2x-1}\left(đkxđ:x\ne-\frac{1}{2};\frac{1}{2}\right)\)

\(< =>\frac{2\left(2x-1\right)}{\left(2x+1\right)\left(2x-1\right)}+\frac{x}{\left(2x+1\right)\left(2x-1\right)}=\frac{7\left(2x+1\right)}{\left(2x+1\right)\left(2x-1\right)}\)

\(< =>4x-2+x=14x+7\)

\(< =>14x-5x=-2-7\)

\(< =>9x=-9< =>x=-\frac{9}{9}=-1\left(tm\right)\)

\(\frac{x-1}{2x+3}-\frac{3x+7}{2x-3}=\frac{10-4x^2}{4x^2-9}\)

\(\frac{x-1}{2x+3}-\frac{3x+7}{2x-3}=\frac{10-4x^2}{\left(2x-3\right)\left(2x+3\right)}\)

\(\frac{\left(x-1\right)\left(2x-3\right)}{\left(2x+3\right)\left(2x-3\right)}-\frac{\left(3x+7\right)\left(2x+3\right)}{\left(2x+3\right)\left(2x-3\right)}=\frac{10-4x^2}{\left(2x+3\right)\left(2x-3\right)}\)

2x²-3x-2x+3-(6x²+9x+14x+21)=10-4x²

2x²-3x-2x+3-6x²-9x-14x-21=10-4x²

2x²-3x-2x+3-6x²-9x-14x-21-10+4x²=0

2x²-6x²+4x²-3x-2x-9x-14x+3-21-10=0

-28x-28=0

-28x=28

x=28:(-28)

x=-1

\(\frac{x-1}{2x+3}-\frac{3x+7}{2x-3}=\frac{-4x^2+10}{4x^2-9}\)

\(\frac{x-1}{2x+3}-\frac{3x+7}{2x-3}=\frac{-2\left(2x^2-5\right)}{4x^2-9}\)

\(\frac{x-1}{2x+3}-\frac{3x+7}{2x-3}=\frac{-4x^2+10}{\left(2x+3\right)\left(2x-3\right)}\)

\(-4x^2-28x-18=-4x^2+10\)

\(-4x^2-28x-18+4x^2-10=0\)

\(-28x-28=0\)

\(-28x=28\)

\(x=-1\)