What's "x squared minus 4x minus 45"

X^2 - 4x - 45 = 0

by using the ' splitting the middle term method ',

_ x _ = - 45

_ + _ = - 4

the blanks ca be filled by using the digits ' - 9 and 5 '

as - 9 x 5 = - 45

and - 9 + 5 = - 4

therefore,

x^2 - 9 x + 4x - 45 = 0

taking the common factor out,

x (x-9) + 4 (x - 9) = 0

therefore,

a) x - 9 = 0

and x = 9

b) x + 4 = 0

and x = - 4