Question

Factorise: -x²+7x-12​

Answer 1

GIven : x2+7x+12

             =x2+4x+3x+12, (split middle term so that resultant is same)

             =(x2+4x)+(3x+12), (group pair of terms)

             =x(x+4)+3(x+4), (factor each binomials) 

             =(x+4)(x+3), (factor out common factor (x+4))

Answer 2

Answer:

(x+4)(x-3)

Step-by-step explanation:

x+4x-3x+12

x(x+4)-3(x+4)

(x+4)(x-3)