Question

subtract 4mn-7mn+3n+12 from 12m-9mn+5n-3?​

Answer 1

$\left(12m-9mn+5n-3\right)-\left(4mn-7mn+3n+12\right)$

$=12m-9mn+5n-3-\left(4mn-7mn+3n+12\right)$

$=12m-9mn+5n-3-\left(3n-3mn+12\right)$

$=12m-9mn+5n-3+3mn-3n-12$

$=12m-6mn+2n-15$

Answer 2

12m - 9mn + 5n -3 -(4mn-7mn+3n+12)

= 12m - 9mn +5n -3 - 4mn +7mn -3n - 12

= 12m - 6mn + 2n - 15