+) Tam giác ABC vuông tại B => BC² = AC² - AB² => BC² = 16² - 12² => BC² = 112 => BC = √112

+) S_tp = S_xq + Sđ = 2p.h + AB. BC = 2. \(\dfrac{2\left(12+\sqrt{112}\right)}{2}\).2 + 12. \(\sqrt{112}\) \(\approx\) 217,32(cm²)

+) V = S.h = 12.\(\sqrt{112}\).2 \(\approx\) 253,9(cm³)

a) Xét 2 trường hợp:

+) Nếu x >= 0 ⇒ -2x <= 0:

|-2x|-x+5=1 ⇔ 2x - x + 5 = 1 ⇔ x = -4 (loại vì x >= 0)

+) Nếu x < 0 ⇒ - 2x > 0 :

|-2x|-x+5=1 ⇔ -2x - x + 5 = 1

⇔ -3x = -4

⇔ x = 4/3 (loại vì x< 0)

Vậy phương trình đã cho vô nghiệm

b) Xét 2 trường hợp:

+) Nếu x >= 0 ⇒ -2x <= 0

x-5x+|-2x|-3=0 ⇔ x - 5x + 2x - 3 = 0

⇔ -2x = 3

⇔ x = -3/2 (loại vì x >= 0)

+) Nếu x< 0 ⇒ -2x > 0

x-5x+|-2x|-3=0 ⇔ x -5x -2x - 3 = 0

⇔ -6x = 3

⇔ x = -1/2 (chọn)

Vậy phương trình đã cho có tập nghiệm S = {-1/2}

Read the passage below and decide whether the statements are TRUE or FALSE?

Lan is a student. That is her family. There are five people in her family: her father, her mother, her sister, her brother and her. That is her father. He's forty years old. He is working as a doctor in the city hospital. That is her mother. She is thirty-five years old. She is a nurse. Her brother is fifteen years old. Her sister is six years old. They are students. Although everybody is busy with their job, they still gather together to share happiness and sorrow in their life.

Her family spends less time for each other

A. True

B. False