A = -(x-y)-z(x-y)=(x-y)(-1-z)=(y-x)(z+1)

4  I last had my hair cut when I left her.

--> I haven't had my haircut since I left her.

2. She has driven for 1 month.

c) (x - 1)³ - x².(x - 2) + 5 = 0.

<=> x^3 - 3x^2 + 3x - 1 - x^3 + 2x^2 + 5 = 0

<=> -x^2 + 3x + 4 = 0 <=> x^2 - 3x - 4 = 0

<=> (x - 4)(x + 1) = 0

<=> x = 4 hoặc x = -1

d)  x² - 4x + 5 = 0.

<=> (x - 2)² = -1 (vô lý)

Vậy phương trình vô nghiệm

b) (2x - 1)² - 3.(x - 2).(x + 2) - 25 = 0.

<=> 4x^2 - 4x + 1 - 3x^2 + 12 - 25 = 0

<=> x² - 4x - 12 = 0

<=> (x+2)(x-6) = 0

<=> x = -2 hoặc x = 6

a)  (x - 3)² - 5.(x - 2) + 5 = 0.

<=> x^2 - 6x + 9 - 5x + 10 + 5 = 0

<=> x^2 - 11x + 24 = 0

<=> (x-3)(x-8)=0

<=> x = 3 hoặc x = 8

A

c) 2x² - 5x + 3 = 0.

<=> (x - 1)(2x - 3) = 0

<=> x = 1 hoặc x = 3/2

b) 3x² - 7x - 10 = 0.

<=> (x + 1)(3x - 10) = 0

<=> x = -1 hoặc x = 10/3