Factorise.

x² – 10x + 9

On comparing with standard quadratic equation that is

we have,0

a = 1, b = – 10 and c = 9

Now here,

Product ac = 19 = 9

Factors of 9; 19 and 33

Sum should be b = – 10

From above factors ( – 1x – 9x)

will give – 10x sum

therefore – 10x is replaced by ( – 1x – 9x)

Now above eq. becomes

; taking x and – 9 common

(x – 1)(x – 9)