Question

Answer 1

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

x² + 2x + x + 2 - x² - 4x + 3x + 12 = 6

2x + 14 = 6

2x = 6 - 14

2x = -8

x = -8 : 2

x = -4

b) (x - 2)² - 25 = 0

(x - 2)² - 5² = 0

(x - 2 - 5)(x - 2 + 5) = 0

(x - 7)(x + 3) = 0

x - 7 = 0 hoặc x + 3 = 0

*) x - 7 = 0

x = 7

*) x + 3 = 0

x = -3

Vậy x = -3; x = 7

c) x² - 2x = 0

x(x - 2) = 0

x = 0 hoặc x - 2 = 0

*) x - 2 = 0

x = 2

Vậy x = 0; x = 2

Answer 2

\(a,\)

\(\left(x+1\right)\left(x+2\right)-\left(x-3\right)\left(x+4\right)=6\)

\(\Rightarrow\left(x^2+3x+2\right)-\left(x^2+x-12\right)=6\)

\(\Rightarrow x^2+3x+2-x^2-x+12=6\)