The constraints $x+y \leq 4$,$3x+3y \geq 18$,$x \geq 0$,$y \geq 0$ define:

$A$ solution is to be kept between $40^{\circ} C$ and $45^{\circ} C$. What is the range of temperature in degree Fahrenheit,if the conversion formula is $F = \frac{9}{5} C + 32$?

$\left\{x \in R : \frac{\sqrt{6+x-x^2}}{2x+5} \geq \frac{\sqrt{6+x-x^2}}{x+4}\right\}=$

The set of all real values of $x$ satisfying the inequation $\frac{8x^2-14x-9}{3x^2-7x-6} > 2$ is

$A$ solution of $8 \%$ boric acid is to be diluted by adding a $2 \%$ boric acid solution to it. The resulting mixture is to be more than $4 \%$ but less than $6 \%$ boric acid. If we have $640$ litres of the $8 \%$ solution,how many litres of the $2 \%$ solution will have to be added?

Find all pairs of consecutive odd positive integers,both of which are smaller than $10$,such that their sum is more than $11$.