tìm GTLN

A=\(3x^2\left(8-x^2\right)\) với \(-2\sqrt{2}\le x\le2\sqrt{2}\)

B=4x(8-5x) với \(0\le x\le\frac{8}{5}\)

C=4(x-1)(8-5x) với \(1\le x\le\frac{8}{5}\)

D=x\(\left(3-\sqrt{3}\right)\) với \(0\le x\le\sqrt{3}\)

Tìm GTNN

A=\(\frac{3x}{2}+\frac{2}{x-1}\) với x>1

B=x+\(\frac{2}{3x-1}\) với x>1/3

Tìm m để bpt luôn đúng với mọi x

a/\(-x^2+2m\sqrt{2}x-2m^2-1< 0\)

b/\(\left(m^2+3\right)x^2+2\left(m+1\right)x+1>0\)

c/\(\left(m-1\right)x^2+2\left(m-1\right)x-4m< 0\)

d/\(\left(m+1\right)x^2-\left(m-1\right)x-1-2m< 0\)

tìm m để hệ phương trình có nghiệm :

a/\(\left\{{}\begin{matrix}x^2-5x+6< 0\\mx+4< 0\end{matrix}\right.\)

b/\(\left\{{}\begin{matrix}4x+1< 7x-2\\x^2-2mx+1\le0\end{matrix}\right.\)

giải Bất phương trình :

\(\sqrt{x^2-5x-14}\ge2x-1\)

\(\sqrt{2x^2+7x+5}>x+1\)

\(\sqrt{x^2+4x-5}\le x+3\)

giải bất phương trình

a/\(\frac{x^4-x^2}{x^2+5x+6}\le0\)

b/\(\frac{4x^2+3x-1}{x^2+5x+7}>0\)

c/\(\frac{x^4+x^2+1}{x^2-4x-5}\le0\)

d/\(\frac{-2x^2+7x+7}{x^2-3x-10}\le-1\)

e/\(\frac{2\left(x-4\right)}{\left(x-1\right)\left(x-7\right)}\ge\frac{1}{x-2}\)

Giai BPT

\(\frac{\left(x-1\right)^3\left(x+2\right)^4}{x^2\left(x-7\right)^5}\ge0\)

EX : Complete each of the following sentences in such a way that it means the same as the sentence printed before it.

1/ we didn't know your phone number ,so we could not contact you

2/ Because Simon doesn't live near his mother,he can't visit her often

3/ she didn't hurry , so she missed the train

6/ John is fat because he eats so many chips

7/ Bill never does anything if you don't tell him what to do.

-> Unless......................................................................................

8/ They don't have enough time so they cannot do me a favour.

9/we did not visit the museum because we had no time

10/ we can't buy this car because it is very expensive

11/ Susan felf sick because he ate 4 cream cakes.