Question

Giúp mình bài 5 nha mọi người

Answer 1

Em tách ra bớt đi nhé, chứ nhiều quá!

Answer 2

nhieu the!

Answer 3

nhiều thế

Answer 4

1) -x(-2x+1)-2x²=5

\(\Leftrightarrow\) 2x²-x-2x²=5

 

\(\Leftrightarrow\) -x=5

 

\(\Leftrightarrow\) x= -5

2) 2x(-x-\(\dfrac{1}{2}\))+2x²=2

 

\(\Leftrightarrow\) -2x² - xx + 2x² = 2

 

\(\Leftrightarrow\) -x = 2

 

\(\Leftrightarrow\) x = -2

3) -3x(-4x-1)+6x(4-2x)=0

 

\(\Leftrightarrow\) 12x² + 3x + 24x - 12x² = 0

 

\(\Leftrightarrow\) 27x = 0

 

\(\Leftrightarrow\) x = 0

4) 5x(-x+1) - 5(-x²-x)=0

 

\(\Leftrightarrow\) -5x² + 5x + 5x² + 5x = 0 

 

\(\Leftrightarrow\) 10x = 0

 

\(\Leftrightarrow\) x = 0

5) -\(\dfrac{7}{3}\)x(3x+1) - \(\dfrac{1}{2}\)x(2-14x)=0

 

\(\Leftrightarrow\) -7x² - \(\dfrac{7}{3}\)x - \(\dfrac{1}{2}\)x.2(1-7x) = 0

 

\(\Leftrightarrow\) -7x² - \(\dfrac{7}{3}\)x - x.(1-7x) = 0

\(\Leftrightarrow\) -7x² - \(\dfrac{7}{3}\)x - x + 7x² = 0

\(\Leftrightarrow\) - \(\dfrac{7}{3}\)x - x = 0

\(\Leftrightarrow\) -7x - 3x = 0

\(\Leftrightarrow\) -10x = 0

\(\Leftrightarrow\) x = 0

Answer 5

6) -10x(2-x) - 5x(x+2) = 5x(x+3)

\(\Leftrightarrow\) -20x + 10x² - 5x² -10xx = 5x² + 15x

\(\Leftrightarrow\) -30x + 5x² = 5x² +15x

\(\Leftrightarrow\) -30x = 15x

\(\Leftrightarrow\) -30x - 15x = 0

\(\Leftrightarrow\) -45x = 0

\(\Leftrightarrow\) x = 0

Answer 6

7) x(5-2x) + 2x(x-1) = 15

\(\Leftrightarrow\) 5x - 2x² + 2x² -2x = 15

\(\Leftrightarrow\) 3x = 15

\(\Leftrightarrow\) x = 5

8) 5x - 3\(\left\{4x-2\left[4x-3\left(5x-2\right)\right]\right\}\) = 182

\(\Leftrightarrow\) 5x - 3 \(\left[4x-2\left(4x-15x+6\right)\right]\) = 182

\(\Leftrightarrow\) 5x - 3 \(\left[4x-2\left(-11+6\right)\right]\) = 182

\(\Leftrightarrow\) 5x - 3 (4x + 22x - 12) = 182

⇔ 5x - 3(26x - 12) = 182

⇔ 5x - 78x + 36 = 182

⇔ -73x + 36 = 182

⇔ -73x = 182 - 36

⇔ -73x = 146

⇔ x=-2