If \( 25 \% \) of two-thirds of a number is 10 , find the number. \( \begin{array}{ll}\text { A) } 75 & \text { B) } 120 \\ \text { C) } 60 & \text { D) } 30\end{array} \)

8. Factorise each of the following expressions. (a) \( x(x-5)+6 \) (b) \( x^{2}+3(x-6) \) (c) \( (x-3)^{2}+12 x \) (d) \( (x+3)(x-4)-8 \) (e) \( (3 x-4)(2 x-5)+8(2 x-5) \) (f) \( (3 x-4)^{2}-(2 x+1)^{2} \)

11. \( y-7=-10 \)

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) \( -3 x^{2}-11 x+4 \)

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