Question

1) 3 - 2x + 4 + 6x = x + 7 + 3x

2) -6(1,5 - 2x) = 3(-15 + 2x)

3) 3(2x - 5) + 5(x -1) = 4(x + 1)

Answer 1

1/ 3-2x+4+6x=x+7+3x

⇔-2x+6x-x-3x=0

⇔0x=0 (Vô số nghiệm)

2/-6(1,5-2x)=3(-15+2x)

⇔-9+12x=-45+6x

⇔6x+36=0

⇔6(x+6)=0

⇔x+6=0

⇔x=-6

Vậy S ϵ {-6}

3/ 3(2x-5)+5(x-1)=4(x+1)

⇔6x-15+5x-5=4x+4

⇔7x=24

⇔x=\(\dfrac{24}{7}\) 

Vậy S ϵ {\(\dfrac{24}{7}\)}

 

Answer 2

1) Ta có: \(3-2x+4+6x=x+7+3x\)

\(\Leftrightarrow4x+7=4x+7\)

\(\Leftrightarrow4x+7-4x-7=0\)

\(\Leftrightarrow0x=0\)(luôn đúng)

Vậy: S={x|\(x\in R\)}

2) Ta có: \(-6\cdot\left(1.5-2x\right)=3\left(-15+2x\right)\)

\(\Leftrightarrow-9+12x=-45+6x\)

\(\Leftrightarrow12x-9+45-6x=0\)

\(\Leftrightarrow6x+36=0\)

\(\Leftrightarrow6x=-36\)

hay x=-6

Vậy: S={-6}

3) Ta có: \(3\left(2x-5\right)+5\left(x-1\right)=4\left(x+1\right)\)

\(\Leftrightarrow6x-15+5x-5=4x+4\)

\(\Leftrightarrow11x-20-4x-4=0\)

\(\Leftrightarrow7x-24=0\)

\(\Leftrightarrow7x=24\)

\(\Leftrightarrow x=\dfrac{24}{7}\)

Vậy: \(S=\left\{\dfrac{24}{7}\right\}\)

Answer 3

1) 3 - 2x + 4 + 6x = x + 7 + 3x

⇔-2x + 6x - x - 3x = 7 - 3 - 4

⇔0x = 0

⇔x ∈ R

Vậy ...

2) -6(1,5 - 2x) = 3(-15 + 2x)

⇔-9 + 12x = -45 + 6x

⇔6x = -36

⇔x = -6

Vậy ...

 

Answer 4

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