a \( -x^{2}-3 x+54 \) d \( -x^{2}+2 x+43 \) Fully factorise: a \( 7 x-35 y \) d \( m m^{2}+3 m y \) g \( 5 x^{2}+5 x y-5 x^{2} y \)

10. \( \frac{7 x+65}{5}=6 \)

7. Factorise each of the following. (a) \( -x^{2}+5 x-6 \) (b) \( -x^{2}+7 x+8 \) (c) \( -2 x^{2}-11 x-5 \) (d) \( -3 x^{2}-11 x+4 \)

56. Вычислите значение выраже \( \frac{\sqrt{5}+\sqrt{7}}{\sqrt{5}-\sqrt{7}}+\frac{\sqrt{5}-\sqrt{7}}{\sqrt{5}+\sqrt{7}} \).

a) \( \begin{aligned} 4 y+20 & =40 \\ 7 z-15 & =55\end{aligned} \)

5. Factorise each of the following expressions by splitting the middle term. \( \begin{array}{ll}\text { (a) } x^{2}+3 x+2 & \text { (b) } x^{2}+5 x+6 \\ \text { (c) } y^{2}-7 y+10 & \text { (d) } y^{2}-8 y-9 \\ \text { (e) } z^{2}+2 z-3 & \text { (f) } z^{2}+14 z-15\end{array} \)