Question

có ai không giúp mình với !!!!!!!!!!!!!!!

Answer 1

a)

⇔\(\dfrac{2x-5}{x+5}-\dfrac{3x+15}{x+5}=0\)

⇔\(\dfrac{3x-5-3x-15}{x+5}=0\)

⇔\(-x-20=0\)

⇔\(x=-20\)

Answer 2

c)

⇔x(x+1) = (x+4)(x-1)

⇔x²+x=x²-x+4x-4

⇔x²+x-x²+x-4x=-4

⇔-2x=-4

⇔x=2

Vậy S={2}

Answer 3

\(\left(a\right)\dfrac{2x-5}{x+5}=\dfrac{3\left(x+5\right)}{x+5}\)

ĐKXĐ: x+5\(\ne0\)<=> \(x\ne-5\)

Gỉai:

\(\dfrac{2x-5}{x+5}=\dfrac{3\left(x+5\right)}{x+5}\)

\(< =>2x-5=3x+15\)

\(< =>-5-15=3x-2x\)

\(< =>-20=x< =>x=-20\)

Vậy pt trên có nghiệm là S={-20}

 

Answer 4

d) 

⇔(2-3x)(2x+1)=(3x+2)(-2x-3)

⇔4x+2-6x²-3x=6x²-9x-4x-6

⇔4x-6x²-3x-6x²+9x+4x=-6-2

⇔14x=-8

⇔x=\(-\dfrac{4}{7}\)

Vậy S= {\(-\dfrac{4}{7}\)}

Answer 5

a) ĐKXĐ: \(x\ne-5\)

Ta có: \(\dfrac{2x-5}{x+5}=\dfrac{3\left(x+5\right)}{5}\)

Suy ra: \(2x-5=3x+15\)

\(\Leftrightarrow2x-3x=15+5\)

\(\Leftrightarrow-x=20\)

hay x=-20(thỏa ĐK)

Vậy: S={-20}