$$2x^2+2x-12$$  

(a)  

$$6x^2+11x+5$$  

(a)  

$$a^2+7a+6$$  

(a)  

$$c^2+11c-12$$  

(a)  

$$2x^2-x-15$$  

(a)  

$$6x^2-29x+28$$  

(a)  

$$x^2-2xy-15y^2$$  

(a)  

$$6x^2+11xy+5y^2$$  

(a)  

$$a^2+7ab+6b^2$$  

(a)  

$$c^2+11cd-12d^2$$  

(a)  

$$6x^2-29xy+28y^2$$  

(a)  

$$2x^2-xy-15y^2$$  

(a)  

$$2x^2+2xy-12y^2$$  

(a)