Question

factorise 12(a+b)^2-5(a+b)-3​

Answer 1

Step-by-step explanation:

Let us assume (a+b)= x

= 12x²-5x-3

Now simply solve it by middle term splitting method

= 12x² +4x -9x -3

= 4x(3x +1) -3(3x+1)

= (4x-3)(3x+1)

thus x= 3/4, -1/3

(

That is a+b= 3/4,-1/3

or we can write it in this form

= (4(a+b)-3)(3(a+b)+1)

Hope this helps you

Answer 2

Step-by-step explanation:

Take(a+b) to be x

Now...

12x^2 - 5x - 3

Using mid term split

12x^2 - 9x+4x - 3

(12x^2 +4x)-(9x+3)

4x(3x+1)-3(3x+1)

(3x+1)(4x-3)

Therefore,x=(-1/3),(3/4)

Now substituting the value of x

(a+b) =-1/3 and (a+b) =3/4

Taking (a+b) =-1/3

3(a+b)=-1

3a+3b=-1 - >equation 1

Taking (a+b) =3/4

4a+4b=3

4a=3-4b

A=(3-4b)/4 - >equation2

Using value of a in equation 1

3(3-4b)+3b=-1

9-12b+3b=-1

9-9b=-1

-9b=-1-9=-10

B=-10/-9=10/9

Using value of b in equation 2

A=(3-4b)4

A=(3-40/9)4

A=(27-40/9)4

A=(-13*4)9

A=-52/9

The answer seems weird now that I see it...