-5/3x⁴

20x⁵ : (-12x)= \(-\dfrac{5}{3}\)x⁴

^{học tốt}

=-5/3x^4

\(5x\left(12x+7\right)-3x\left(20x-5\right)=-100\\ \Leftrightarrow60x^2+35x-60x^2+15x=-100\\ \Leftrightarrow50x=-100\\ \Leftrightarrow x=-2\)

Vậy x = -2 là nghiệm của pt.

Ta có: \(5x\left(12x+7\right)-3x\left(20x-5\right)=-100\)

\(\Leftrightarrow60x^2+35x-60x^2+15x=-100\)

\(\Leftrightarrow50x=-100\)

hay x=-2

   \(5x.\left(12x+7\right)-3x.\left(20x-5\right)=-100\)

\(5x.12x+5x.7+\left(-3x\right).20x+\left(-3x\right).\left(-5\right)=-100\)

                            \(60x^2+35x-60x^2+15x=-100\)

                      \(\left(60x^2-60x^2\right)+\left(35x+15x\right)=-100\)

                                                              \(50x=-100\)

                                                                  \(x=\left(-100\right):50\)

                                                                  \(x=-2\)

                                                           Vậy:\(x=-2\)

\(5x\left(12x+7\right)-\left(3x+1\right)\left(20x-5\right)=-100\\ 60x^2+35x-\left(60x^2-15x+20x-5\right)=-100\\ 60x^2+35x-60x^2+15x-20x+5=-100\\ 30x=-105\\ \Rightarrow x=\frac{-7}{2}\)

Vậy \(x=\frac{-7}{2}\)

\(5x\left(12x+7\right)-\left(3x+1\right)\left(20x-5\right)=-100\)

\(\Leftrightarrow60x^2+35x-\left(60x^2-15x+20x-5\right)=-100\)

\(\Leftrightarrow60x^2+35x-60x^2+15x-20x+5=-100\)

\(\Leftrightarrow30x=-100-5\)

\(\Leftrightarrow30x=-105\)

\(\Leftrightarrow x=\frac{-105}{30}=\frac{-7}{2}\)

\(5x\left(12x+7\right)-3x\left(20x-5\right)=-100\)

\(\Leftrightarrow60x^2+35x-60x^2+15x=-100\)

\(\Leftrightarrow50x=-100\)

hay x=-2

60x+35-60x-5

(=)25

\(5x\left(12x+7\right)-\left(3x+1\right)\left(20x-5\right)\)

\(=60x^2+35x-\left(60x^2-15x+20x-5\right)\)

\(=60x^2+35x-60x^2+15x-20x+5\)

\(=20x+5\)

học tốt

\(5x\left(12x+7\right)-\left(3x+1\right)\left(20x-5\right)\)

\(=60x^2-35x-\left(60x^2-15x+20x-5\right)\)

\(=60x^2-35x-60x^2+15x-20x+5\)

\(=\left(60x^2-60x^2\right)-35x+15x-20x+5\)

\(=-20x+5\)