Subtract the sum of #5n^2 -3n -2# and #-7n^2 +n+2# from #12n^2 -n +9# ?

1 Answer
Apr 21, 2018

#color(brown)(=> -14n^2 -n - 9 " or " color(green)(-(14n^2 + n + 9)#

Explanation:

#5n^2 - 3n - 2 + (-7n^2 + n + 2), " Adding first two terms"#

#=>5n^2 - 3n - 2 - 7n^2 + n + 2, " removing bracket"#

#=>5n^2 - 7n^2 - 3n + n - cancel 2 + cancel 2, " rearranging like terms together"#

#=>-2n^2 -2n#

#-2n^2 - 2n - (12n^2 -n + 9, " subtracting the tnird term from the result"#

#=> - 2n^2 - 2n - 12n^2 + n - 9, " removing bracket"#

#=> -2n^2 - 12n^2 - 2n + n - 9, " rearranging terms"#

#color(brown)(=> -14n^2 -n - 9#