How do you combine like terms in #(7b - 8b ^ { 4} + 5b ^ { 2} ) - ( 2b + 7b ^ { 4} - 4b ^ { 2} )#?

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Answer 1 · 2017-03-06T20:05:53

See the entire solution process below:

First, remove all of the terms from parenthesis. be careful to handle the signs of the individual terms correctly:

#7b - 8b^4 + 5b^2 - 2b - 7b^4 + 4b^2#

Next, group like terms:

#-8b^4 - 7b^4 + 5b^2 + 4b^2 + 7b - 2b#

Now, combine like terms:

#(-8 - 7)b^4 + (5 + 4)b^2 + (7 - 2)b#

#-15b^4 + 9b^2 + 5b#

Answer 2 · 2017-03-06T20:16:22

See the explanation below.

#(7b-8b^4+5b^2)-(2b+7b^4-4b^2)=color(blue)(-15b^4+9b^2+5b)#

Combine like terms:

#(7b-8b^4+5b^2)-(2b+7b^4-4b^2)#

Remove the parentheses and simplify.

#7b-8b^4+5b^2-2b-7b^4+4b^2#

Gather like terms.

#(7b-2b)+(-8b^4-7b^4)+(5b^2+4b^2)#

Combine like terms.

#5b-15b^4+9b^2#

Rewrite the expression in descending order of exponents.

#-15b^4+9b^2+5b#