Question

factorise 16 x square -25-40x

Answer 1

First we set this equation into right form that is
16x^2-40x-25
By splitting middle term
Here, multiply of first and last digit we get,400x^2
The two digit that which when we multiply we get 400 and when we subtract we get 40 and the two digit is 20 and 20
NOW,
16x^2-(20-20)x-25
16x^2-20x+20x-25
Now we can take common at outside
4x(4x-5)+5(4x-5)
(4x-5)(4x+5)...answer...
I hope u understand....if not the see the pic...