He never listens to what you say. He always thinks about something else.

Giải thích: Thì hiện tại đơn

We haven't met each other since we left school.

Giải thích: Thì hiện tại hoàn thành + since + thì quá khứ đơn

\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+100\right)=5150\)

\(\left(x+x+x+...+x\right)+\left(1+2+3+...+100\right)=5150\)

\(100x+\left(100+1\right).100:2=5150\)

\(100x+5050=5150\)

\(100x=100\)

\(x=1\)

Bài 1:

a) \(A=x^2-12x+2\)

\(=\left(x^2-12x+36\right)-34\)

\(=\left(x-6\right)^2-34\ge-34\)

Dấu bằng xảy ra \(\Leftrightarrow x=6\)

Vậy \(MinA=-34\Leftrightarrow x=6\)

b) \(B=x^2-6\ge-6\)

Dấu bằng xảy ra \(\Leftrightarrow x=0\)

Vậy \(MinB=-6\Leftrightarrow x=0\)

c) \(C=5x^2+15x+8\)

\(=5\left(x^2+3x+\dfrac{8}{5}\right)\)

\(=5\left[\left(x^2+2.\dfrac{3}{2}x+\dfrac{9}{4}\right)+\dfrac{8}{5}-\dfrac{9}{4}\right]\)

\(=5\left[\left(x+\dfrac{3}{2}\right)^2-\dfrac{13}{20}\right]\)

\(=5\left(x+\dfrac{3}{2}\right)^2-\dfrac{13}{4}\ge-\dfrac{13}{4}\)

Dấu bằng xảy ra \(\Leftrightarrow x=-\dfrac{3}{2}\)

Vậy \(MinC=-\dfrac{13}{4}\Leftrightarrow x=-\dfrac{3}{2}\)

d) \(D=2x^2+6x-1\)

\(=2\left(x^2+3x-\dfrac{1}{2}\right)\)

\(=2\left[\left(x^2+2.\dfrac{3}{2}x+\dfrac{9}{4}\right)-\dfrac{11}{4}\right]\)

\(=2\left[\left(x+\dfrac{3}{2}\right)^2-\dfrac{11}{4}\right]\)

\(=2\left(x+\dfrac{3}{2}\right)^2-\dfrac{11}{2}\ge-\dfrac{11}{2}\)

Dấu bằng xảy ra \(\Leftrightarrow x=-\dfrac{3}{2}\)

Vậy \(MinD=-\dfrac{11}{2}\Leftrightarrow x=-\dfrac{3}{2}\)

e) \(E=4x^2-4x+4\)

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

\(=\left(2x-1\right)^2+3\ge3\)

Dấu bằng xảy ra \(\Leftrightarrow x=\dfrac{1}{2}\)

Vậy \(MinE=3\Leftrightarrow x=\dfrac{1}{2}\)

f) \(F=8x^2-24x-6\)

\(=8\left(x^2-3x-\dfrac{3}{4}\right)\)

\(=8\left[\left(x^2-2.\dfrac{3}{2}x+\dfrac{9}{4}\right)-3\right]\)

\(=8\left[\left(x-\dfrac{3}{2}\right)^2-3\right]\)

\(=8\left(x-\dfrac{3}{2}\right)^2-24\ge-24\)

Dấu bằng xảy ra \(\Leftrightarrow x=\dfrac{3}{2}\)

Vậy \(MinF=-24\Leftrightarrow x=\dfrac{3}{2}\)

1/ \(\left(4x-1\right)^3-\left(4x-3\right)\left(16x^2+3\right)\)

\(=\left(64x^3-48x^2+12x-1\right)-\left(64x^3+12x-48x^2-9\right)\)

\(=64x^3-48x^2+12x-1-64x^3-12x+48x^2+9\)

\(=8\)

2/ \(\left(x+2\right)^3-2\left(x^2+6x-5\right)-8\)

\(=\left(x^3+6x^2+12x+8\right)-\left(2x^2+12x-10\right)-8\)

\(=x^3+6x^2+12x+8-2x^2-12x+10-8\)

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

3/ \(\left(-x-3\right)^3+\left(x+9\right)\left(x^2+27\right)\)

\(=-\left(x^3+9x^2+27x+27\right)+\left(x^3+27x+9x^2+243\right)\)

\(=-x^3-9x^2-27x-27+x^3+27x+9x^2+243\)

\(=216\)

4/ \(\left(x-1\right)^3-\left(x+2\right)\left(x^2-2x+4\right)+3x^2+2x\)

\(=\left(x^3-3x^2+3x-1\right)-\left(x^3+8\right)+3x^2+2x\)

\(=x^3-3x^2+3x-1-x^3-8+3x^2+2x\)

\(=5x-9\)

5/ \(\left(x+2\right)\left(x^2-2x+4\right)-x\left(x^2+2\right)\)

\(=\left(x^3+8\right)-\left(x^3+2x\right)\)

\(=x^3+8-x^3-2x\)

\(=8-2x\)

That house is too expensive for him to buy.

Complete the sentences with the correct form of the words at the end of each line:

1. No one with a recent criminal record will be considered for this job. (CRIME)

2. We have decided to interview only the best six applicants for the job. (APPLY)

3. David’s astonishment at winning the competition was clear to anyone. (ASTONISH)

4. That large dog is perfectly harmless and has never been known to attack anyone. (HARM)

5. Work is going to strengthen the bridge, which carries a great deal of traffic.

(STRONG)

6. The crowd showed its approval by shouting insults at the president. (APPROVE)

7. Dozens of cyclists are injured on the city’s roads each year. (CYCLE)

8. The company is not talking on any new employee this year. (EMPLOY)

9. Carl is studying to become a lawyer (LAW).

10. Motor – racing is an extremely risky sport. (RISK)

Having finished his work, he came here.

Was this letter written an hour ago?

sr nha tại bị lag

parents, different, visited, coach, Museum, ate