Question

Tìm \(x\) , biết:

a) \(\left(x+2\right)\left(x+3\right)-\left(x-2\right)\left(x+5\right)=6\)

b) \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)

c) \(3\left(2x-1\right)\left(3x-1\right)-\left(2x-3\right)\left(9x-1\right)=0\)

CÁC BẠN LÀM NHANH GIÚP MIK NHA!

Answer 1

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

x² + 3x + 2x + 6 - (x² + 5x - 2x - 10) = 6

x² + 5x + 6 - x² - 3x + 10 = 6

2x +16 = 6

\(\Rightarrow\) 2x = -10

\(\Rightarrow\) x = -5

b) (3x + 2)(2x + 9) - (x + 2)(6x + 1) = (x + 1) - (x - 6)

6x² + 27x + 4x + 18 - (6x² + x + 12x + 2) = x + 1 - x + 6

6x² + 31x + 18 - 6x² - 13x - 2 = 7

18x + 16 = 7

\(\Rightarrow\) 18x = -9

\(\Rightarrow\) x = -0.5

c) 3(2x - 1)(3x - 1) - (2x - 3)(9x - 1) = 0

3(6x² - 2x - 3x + 1) - (18x² - 2x - 27x + 3) = 0

3(6x² - 5x + 1) - (18x² - 29x + 3) = 0

18x² - 15x + 3 - 18x² + 29x - 3 = 0

14x = 0

\(\Rightarrow\) x = 0