\(a) f ( x ) = 2 x ^4 + 3 x ^2 − x + 1 − x ^2 − x ^4 − 6 x ^3\)

\(= ( 2 x ^4 − x ^4 ) − 6 x ^3 + ( 3 x ^2 − x ^2 ) − x + 1\)

\(= x ^4 − 6 x ^3 + 2 x ^2 − x + 1\)

\(g ( x ) = 10 x ^3 + 3 − x ^4 − 4 x ^3 + 4 x − 2 x ^2\)

\(= − x ^4 + ( 10 x ^3 − 4 x ^3 ) − 2 x ^2 + 4 x + 3\)

\(= − x ^4 + 6 x ^3 − 2 x ^2 + 4 x + 3\)

\(b) f ( x ) + g ( x ) = x ^4 − 6 x ^3 + 2 x ^2 − x + 1 − x ^4 + 6 x ^3 − 2 x ^2 + 4 x + 3\)

\(= ( x ^4 − x ^4 ) + ( − 6 x ^3 + 6 x ^3 ) + ( 2 x ^2 − 2 x ^2 ) + ( − x + 4 x ) + ( 1 + 3 )\)

\(= 3 x + 4\)

c)Có \(h ( x ) = f ( x ) + g ( x ) = 3 x + 4\)

\(Cho h ( x ) = 0 ⇒ 3 x + 4 = 0\)

\(⇒ 3 x = − 4\) 

\(⇒ x = − \frac{4 }{3} \)

Vậy  \(x=-\frac{4}{3}\) là nghiệm của \(h ( x ) \)

a: Áp dụng định lí Pytago vào ΔBDC vuông tại C, ta được:

hay DB=15(cm)

Xét ΔBDC có 

BE là đường phân giác ứng với cạnh DC

nên 

b: Xét ΔAHB vuông tại H và ΔBCD vuông tại C có 

Do đó: ΔAHBΔBCD

C

B

ko t

A

B

So today I’m going to tell you about the time I got up extremely early in the morning, it happened a few months ago when I went on a trip with my family.

Well… I’ve got to be honest with you, I’m not an early bird, I always sleep in whenever I have the chance, and my job doesn’t require me to wake up early either. That’s why I hardly ever get up before 7 AM.

Anyway, back in January, when my family and I decided to take a trip to Singapore, I was really excited since I had never been to Singapore before and I had heard so many wonderful things about this country.

While my mom took care of the hotel bookings, I was in charge of airplane tickets for the whole family. Unfortunately, all tickets were almost sold-out except for the 7AM flight, which meant we all had to wake up at 4AM in the morning!

At first, I thought it was going to be so difficult since I never have to wake up before sunrise. But to my surprise, on the day of the trip, I was the first one to get up, even before the alarm went off and had to wake everybody up. I guess I was just so excited that even waking up early was not a challenge for a heavy sleeper like me!

All in all, our trip went really well, everyone had a blast there. We travelled around the city, had lots of tasty local dishes and met wonderful people. I would definitely come back to Singapore, even if it means I have to wake up at 4AM again.

B. Her poorness

Tham khảo

Vòng lặp thực hiện :

Vòng 1: j:=j+3 → j=0+3=3

Vòng 2: j:=j+3 → j=3+3=6

Vòng 3: j:=j+3 → j=6+3=9

Vòng 4: j:=j+3 → j=9+3=12

Vòng 5: j:=j+3 → j=12+3=15

Vậy kết quả của j sau khi thực hiện câu lệnh là : 15