Factorise.

m² – 23m + 120

On comparing with standard quadratic equation that is

a

we have,

a = 1, b = – 23 and c = + 120

Now here,

Product a × c = 1 × + 120 = + 120

Factors of + 120; 1 × 120; 2 × 60; 4 × 30; 8 × 15; 24 × 5; 40 × 3

Sum should be b = – 23

From above factors ( – 15m – 8m)

will give – 23m sum

therefore – 23m is replaced by ( – 15m – 8m)

Now above eq. becomes

; taking m and – 8 common

(m – 15)(m – 8)