Answer:

\(6x^2-\left(2x+3\right)\left(3x-2\right)=7\)

\(\Rightarrow6x^2-\left(6x^2+9x-4x-6\right)=7\)

\(\Rightarrow6x^2-\left(6x^2+5x-6\right)=7\)

\(\Rightarrow6x^2-6x^2-5x+6=7\)

\(\Rightarrow-5x+6=7\)

\(\Rightarrow-5x=1\)

\(\Rightarrow x=\frac{-1}{5}\)

\(5x\left(12+7\right)-3x\left(80x-5\right)=-100\)

\(\Rightarrow5x.19-240x^2+15x=-100\)

\(\Rightarrow95x-240x^2+15x=-100\)

\(\Rightarrow-240x^2+110x+100=0\)

\(\Rightarrow-24x^2-11x-10=0\)

\(\Rightarrow24\left(x^2-\frac{11}{24}x+\frac{121}{2304}\right)-\frac{1081}{96}=0\)

\(\Rightarrow24\left(x-\frac{11}{48}\right)^2-\frac{1081}{96}=0\)

\(\Rightarrow24\left(x-\frac{11}{48}\right)^2=\frac{1081}{2304}\)

\(\Rightarrow\left(x-\frac{11}{48}\right)^2=\left(\frac{\pm\sqrt{1081}}{48}\right)^2\)

\(\Rightarrow\orbr{\begin{cases}x-\frac{11}{48}=\frac{\sqrt{1081}}{48}\\x-\frac{11}{48}=\frac{-\sqrt{1081}}{48}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{\sqrt{1081}+11}{48}\\x=\frac{11-\sqrt{1081}}{48}\end{cases}}\)

\(\left(3x-5\right)\left(7-5x\right)-\left(5x-2\right)\left(2-3x\right)=4\)

\(\Rightarrow\left(21x-15x^2-35+25x\right)-\left(10x-15x^2-4+6x\right)-4=0\)

\(\Rightarrow36x-15x^2-35-16x+15x^2+4-4=0\)

\(\Rightarrow\left(-15x^2+15x^2\right)+\left(36x-16x\right)+\left(-35+4-4\right)=0\)

\(\Rightarrow30x-35=0\)

\(\Rightarrow x=\frac{7}{6}\)

a: \(\Leftrightarrow6x^2-6x^2+4x-9x+6=7\)

=>-5x=1

hay x=-1/5

b: \(\Leftrightarrow5x\left(12x+7\right)-3x\left(80x-5\right)=-100\)

\(\Leftrightarrow60x^2+35x-240x^2+15x=-100\)

\(\Leftrightarrow-180x^2+50x+100=0\)

hay \(x\in\left\{\dfrac{5+\sqrt{745}}{36};\dfrac{5-\sqrt{745}}{36}\right\}\)

c: \(\Leftrightarrow21x-15x^2-35+25x-\left(10x-15x^2-4+6x\right)=4\)

\(\Leftrightarrow-15x^2+46x-35+15x^2-16x+4=4\)

=>30x-31=4

=>30x=35

hay x=7/6

6x^2-(2x+5)(3x-2)=7

6x^2 - (6x^2 + 15x -4x -10) =7

-11x = -3

x= 3/11
(3x-5)*(7-5x)-(5x+2)(2-3x)=4

21x - 35 - 15x^2 + 25x - (10x +4 - 15x^2 - 6x) =4

46x - 10x +6x  = 4 + 35 +4

42x = 43

x= 42/42

a, \(4\left(18-5x\right)-12\left(3x-7\right)=15\left(2x-16\right)-6\left(x+14\right)\)

\(\Rightarrow72-20x-36x+84=30x-240-6x-84\)

\(\Rightarrow-20x-36x-30x+6x=-240-84-72-84\)

\(\Rightarrow-80x=-480\Rightarrow x=6\)

b, \(5\left(3x+5\right)-4\left(2x-3\right)=5x+3\left(2x+12\right)+1\)

\(\Rightarrow15x+25-8x+12=5x+6x+36+1\)

\(\Rightarrow15x-8x-5x-6x=36+1-25-12\)

\(\Rightarrow-4x=0\Rightarrow x=0\)

c, \(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)

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

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

\(\Rightarrow-14x=-4\Rightarrow x=\dfrac{2}{7}\)

d, \(5x-3\left\{4x-2\left[4x-3\left(5x-2\right)\right]\right\}=182\)

\(\Rightarrow5x-3\left[4x-2\left(4x-15x+6\right)\right]=182\)

\(\Rightarrow5x-3\left(4x-8x+30x-12\right)=182\)

\(\Rightarrow5x-12x+24x-90x+36=182\)

\(\Rightarrow-73x=182-36\)

\(\Rightarrow-73x=146\Rightarrow x=-2\)

Chúc bạn học tốt!!!

1) 30x-30x^2-31

2)6x^4-2x^3-15x^2+23x-6

a: =3x^3-15x^2+21x

b: =-x^3+6x^2+5x-4x^2-24x-20

=-x^3+2x^2-19x-20

c: =9x^2+15x-3x-5-7x^2-14

=2x^2+12x-19

d: =10x^2-4x+2/3

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