Factorise.

m² – 25m + 100

On comparing with standard quadratic equation that is

we have,

a = 1, b = – 25 and c = 100

Now here,

Product a × c = 1 × 100 = 100

Factors of 100; 1 × 100; 2 × 50; 4 × 25;20 × 5

Sum should be b = – 25

From above factors ( – 20m – 5m)

will give – 25m sum

therefore – 25m is replaced by ( – 20m – 5m)

Now above eq. becomes

; taking m and – 5 common

(m – 5)(m – 20)