Question

-5x2-x+4 factorise the following, using identities

Answer 1

Answer:

-5x^2-x+4

Step-by-step explanation:

-5x^2-5x+4x+4

-5x(x+1)+4(x+1)

(-5x+4)(x+1)=0

-5x+4=0

x=4/5

x+1=0

x=-1

Answer 2

Answer:

-(5x-4)(x+1)

Step-by-step explanation:

-5x²-x+4

Factor out the negative

-(5x²+x-4)

Factor the expression in  the parentheses

Find two numbers that multiply to -20 and add to 1:

5 and -4

-(5x²+x-4)=-(5x²+5x-4x-4)

=-(5x)(x+1)-4(x+1)

=-(5x-4)(x+1)