Question

factorise this m2-23m+42

Answer 1

given,

m² - 23m + 42

using the 4th identity , (x+a)(x+b) = x² + x(a+b)+ab,

we will observe that
- 21 × -2 = + 42
and
-21 + -2 = -23

we have,

(m)² + m( -21-2) + -21 × -2

= (m - 21 ) ( m - 2 )

Answer 2

=M^2-(21+2)m +42
=m^2-21m-2m+42
=m(m-21) -2(m-21)
=(m-2) (m-21)