How do you simplify #(5x^4 -2x^2)- (3x -2x^2- 4x^3+ 6x^4#)?

1 Answer
Aug 21, 2016

#-x^4 +4x^3 -3x#

Explanation:

One way of understanding and doing subtractions is to
"Add on the Inverse"

This means all subtractions can be changed to additions by using the additive inverses. (change the signs)

#5 - (+7) = 5 + (-7) =-2#

OR you can remember that a minus sign before a bracket changes the signs inside the bracket.

Get rid of the brackets and use the red minus sign (same as -1) with the distributive law into the second bracket.

#(5x^4 -2x^2)color(red)(- )(3x -2x^2- 4x^3+ 6x^4#)

=#5x^4 -2x^2 - 3x +2x^2+ 4x^3- 6x^4 " collect like terms"#

=#-x^4 +4x^3 -3x#