kho qua

a) Không phải

b) BPT bậc nhất một ẩn với a = 3 và b = -9.

c) Không phải.

d) Không phải.

3595                                      tik nha

a: \(\Leftrightarrow-15x+10=-7x+14\)

=>-8x=4

hay x=-1/2

\(a,\dfrac{2-3x}{x-2}=-\dfrac{7}{5}\left(x\ne2\right)\\ \Leftrightarrow14-7x=10-15x\\ \Leftrightarrow8x=-4\Leftrightarrow x=-2\left(tm\right)\\ c,\Leftrightarrow\dfrac{x-1}{2}=\dfrac{y-2}{5}=\dfrac{z-3}{4}=\dfrac{2x-2+3y-6-z+3}{2\cdot2+5\cdot3-4}=\dfrac{45}{15}=3\\ \Leftrightarrow\left\{{}\begin{matrix}x-1=6\\y-2=15\\z-3=12\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=7\\y=17\\z=15\end{matrix}\right.\\ d,\Leftrightarrow\dfrac{x}{1}=\dfrac{y}{3};\dfrac{y}{4}=\dfrac{z}{5}\\ \Leftrightarrow\dfrac{x}{4}=\dfrac{y}{12}=\dfrac{z}{15}=\dfrac{6x+7y+8z}{24+84+120}=\dfrac{456}{228}=2\\ \Leftrightarrow\left\{{}\begin{matrix}x=8\\y=24\\z=30\end{matrix}\right.\)

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

1) 2(3x+5)-6=9 

  2(3x+5)    =9+6

  2(3x+5)    =15

    3x+5     = 15:2

   3x+5    = \(\frac{15}{2}\)

  3x      = \(\frac{15}{2}-5\)

  3x        =\(\frac{5}{2}\)

   x        = \(\frac{5}{2}:3\)

   x       = \(\frac{5}{6}\)

2) 5x+3(4+2x)=25

   5x+12+6x=25

   5x+6x      =-12+25

   11x          =13

      x           =13:11

      x           =\(\frac{13}{11}\)

3) 3(4x+1)+2(x-1)=105

   12x+3+2x-2=105

   12x+2x      = -3+2+105

    14x           =104

       x            = 104:14

       x            = \(\frac{52}{7}\)

4) \(30-[2\left(x-3\right)-2]=14\)

                 \(2\left(x-3\right)-2\)=\(30-14\)

                 \(2\left(x-3\right)-2=16\)

                 \(2\left(x-3\right)=16+2\)

                  \(2\left(x-3\right)=18\)

                  \(x-3=18:2\)

                  \(x-3=9\)

                  \(x=9+3\)

                  \(x=12\)

     k mình nha !!!!!!