Domestic cats are much smaller than lions

Some of the biggest animals in the world are the elephants

Real beasts are more interesting than mythical animals

Are mosquitos the most dangerous animals in Africa?

The cheetah is the fastest land animal

Giraffes have longer necks than kangaroos

a: góc DAC=90-40=50 độ

b: góc ADB=90 độ

c: góc DAB=90-80=10 độ

=>góc BAE=10+50=60 độ

góc AED=180-60=120 độ

Who are you often meet on Saturday?

Why your father usually have beefsteak for his breakfast?

How many big beds in your bedroom?

a, - \(\dfrac{1}{3}\).\(xy\).(3\(x^3\).y² - 6\(x^2\) + y²)

= - \(x^4\).y³ + 2\(x^3\).y - \(\dfrac{1}{3}\).\(xy^3\)

b, (2\(x\) -3).(4\(x\)² + 6\(x\) + 9)

 = (2\(x\))³ - 3³

= 8\(x^3\) - 27