\(3x\left(x+1\right)-2x\left(x+1\right)=-x-1\)

\(\Leftrightarrow\left(x+1\right)\left(3x-2x\right)=-\left(x+1\right)\)

\(\Leftrightarrow\left(x+1\right)x+\left(x+1\right)=0\)

\(\Leftrightarrow\left(x+1\right)^2=0\)

\(\Leftrightarrow x+1=0\)

\(\Leftrightarrow x=-1\)

Ta có: \(n_{H_2}=\dfrac{2,479}{24,79}=0,1\left(mol\right)\)

Theo ĐLBT KL: m_Zn + m_H2SO4 = m_ZnSO4 + m_H2

⇒ m_H2SO4 = 9 + 0,1.2 - 6,5 = 2,7 (g)

(4x⁴ + 12x²y² + 9y⁴) : (2x² + 3y²)

= (2x² + 3y²)² : (2x² + 3y²)

= 2x² + 3y²

Ex1

1 prevent

2 environment

3 recycle

4 affects

5 harm

6 caused

7 issue

8 health

9 burned

10 coughed

11 damade

12 lung

13 disease

14 pollution

15 heart

Ex2

1 polluted

2 healthily

3 Prevention

4 environmentally

5 reduction

6 saving

7 harmlessly

8 electrician

9 poisonous 

10 protection

11 wasteful

12 tourism

13 organized

14 removement

15 cleaner

\(5a^2+5ab-a-b\\ =5a\left(a+b\right)-\left(a+b\right)\\ =\left(a+b\right)\left(5a-1\right)\)

Có thể vẽ hình cho em được không ạ 

\(\left(2x+3\right)^2-4x^2=10\\ \Leftrightarrow\left(4x^2+12x+9\right)-4x^2=10\\ \Leftrightarrow4x^2-4x^2+12x=10-9\\ \Leftrightarrow12x=1\\ \Leftrightarrow x=\dfrac{1}{12}\)