Question

SO, when you factorise using splitting the middle term (class 8 cbse) we do this:

Ex. p²-17p-38
We can compare it to (x+a)(x+b) = x²+ (a+b)x + ab

So, x=p
-17 = A+B
and -38 = AB

How will we find a and b without doing trial and error? Please help.

Answer 1

Answer:

if you are doing this in splitting the middle term method, then we have to split -17p in such a way that the two terms derived after splitting will give a product of the third term (-38)

in this case, -19x2 = -38

so, p^2 - 17p -38 can be written as

p^2 - 19p + 2p - 38

now factorise two terms

p ( p - 19 ) + 2 ( p - 19)

(p-19) (p+2)

this is your answer