Solve the following .... Gramer's rule. \( \begin{array}{c}x+2 y+3 z=6 \\ 2 x+4 y+z=7 \\ 3 x+2 y+9 z=14\end{array} \)

Вычисли дискриминант квадратного уравнения: \( 5 \mathrm{x}-2+11 \mathrm{x}^{2}=0 \) Запиши в поле ответа верное число. \( \mathrm{D}= \)

9. If \( x-y=4 \) and \( x y=21 \), then \( x^{3}-y^{3} \) is \( \begin{array}{ll}\text { (a) } 361 & \text { (b) } 316 \\ \text { (c) }-188 & \text { (d) } 360\end{array} \)

2 Find the solution set in \( R:|2 x-3|+3>7 \)

b. \( \sqrt{1^{3}}+2^{1}+3^{3}+\cdots+n^{\overline{3}} \)

(C) If \( a, b, c \) and \( d \) are proportion quantities, then prove that: \( \frac{a+2 c}{b+2 d}=\frac{c-a}{d-b} \) (a) If \( \frac{a}{x+y}=\frac{b}{y-2 x}=\frac{c}{x+4 y} \), find the value of : \( \frac{b+2 c}{2 a+b} \) (b) If \( y=3+a \) and \( a \propto \frac{1}{x} \) and \( y=5 \) when \( x=1 \), find the relation bet \( x \) and \( y \), then find the value of \( y \) when \( x=2 \)