\(4\left(x-1\right)\left(x+5\right)-\left(x+2\right)\left(x+5\right)=3\left(x-1\right)\left(x+2\right)\)
\(\Leftrightarrow4\left(x-1\right)\left(x+5\right)-\left(x+2\right)\left(x+5\right)-3\left(x-1\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left(4x-4\right)\left(x+5\right)-\left(x^2+5x+2x+10\right)-\left(3x-3\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left(4x^2+20x-4x-20\right)-\left(x^2+5x+2x+10\right)-\left(3x^2+6x-3x-6\right)=0\)
\(\Leftrightarrow4x^2+20x-4x-20-x^2-5x-2x-10-3x^2-6x+3x+6=0\)
\(\Leftrightarrow6x-24=0\)
\(\Leftrightarrow6x=24\)
\(\Leftrightarrow x=\dfrac{24}{6}=4\)
Vậy \(x=4\)
\(4\left(x-1\right)\left(x+5\right)-\left(x+2\right)\left(x+5\right)=3\left(x-1\right)\left(x+2\right)\)
\(\Rightarrow\left(x+5\right)\left[4\left(x-1\right)-\left(x+2\right)\right]=3\left(x-1\right)\left(x+2\right)\)
\(\Rightarrow\left(x+5\right)\left(4x-4-x-2\right)=3\left(x-1\right)\left(x+2\right)\)
\(\Rightarrow\left(x+5\right)\left(3x-6\right)=3\left(x-1\right)\left(x+2\right)\)
\(\Rightarrow3\left(x+5\right)\left(x-2\right)=3\left(x-1\right)\left(x+2\right)\)
\(\Rightarrow\left(x+5\right)\left(x-2\right)-\left(x-1\right)\left(x+2\right)=0\)
\(\Rightarrow x^2+3x-10-x^2-x+2=0\)
\(\Rightarrow2x-8=0\)
\(\Rightarrow2\left(x-4\right)=0\)
\(\Rightarrow x-4=0\)
\(\Rightarrow x=4\)
\(\Rightarrow\dfrac{\left(x+5\right)\left[4\left(x-1\right)-\left(x+2\right)\right]}{\left(x-1\right)\left(x+2\right)}=\dfrac{3}{4}\)
\(\Rightarrow\dfrac{\left(x+5\right)\left(x-1-x-2\right)}{\left(x-1\right)\left(x+2\right)}=\dfrac{3}{4}\)
\(\Rightarrow\dfrac{-3\left(x+5\right)}{\left(x-1\right)\left(x+2\right)}=\dfrac{3}{4}\)
4(x−1)(x+5)−(x+2)(x+5) = 3(x−1)(x+2)
⇒ (x+5)[4(x−1)−(x+2)] = 3(x−1)(x+2)
⇒ (x+5)(4x−4−x−2) = 3(x−1)(x+2)
⇒ (x+5)(3x−6) = 3(x−1)(x+2)
⇒ 3(x+5)(x−2) = 3(x−1)(x+2)
⇒ (x+5)(x−2)−(x−1)(x+2) = 0
⇒ x2+3x−10−x2−x+2 = 0
⇒ 2x−8 = 0
⇒ 2(x−4) = 0
⇒x−4=0
⇒x=4
