Clarification: please simplify (20v^2-9v^3) - (7v^3-10v^4-14v^2)

[Scoopula]

Please simplify:

(20v²-9v³) - (7v³-10v⁴-14v²)

Please check; My answer is 34v²-2v³+10v^{4
Thank you!}

 

[Deleted member 4993]

Please simplify: (20v²-9v³) - (7v³-10v⁴-14v²) Please check; My answer is 34v²-2v³+10v^{4 Thank you!}

(20v^2 - 9v^3) - (7v^3 - 10v^4 - 14v^2) = 20v^2 - 9v^3 - 7v^3 + 10v^4 + 14v^2 = 20v^2 + 14v^2 - 9v^3 - 7v^3 + 10v^4 = 10 v^4 + 34 v^2 - 16 v^3

 

[JeffM]

Please simplify:

(20v²-9v³) - (7v³-10v⁴-14v²)

Please check; My answer is 34v²-2v³+10v^{4
Thank you!}

You do not say how you got your answer so we cannot explicitly point out where you went wrong. Even if it were right, it is not fully simplified

You can check your OWN work by substituting a number other than 0 or 1 or - 1. Let's try 2.

\(\displaystyle (20 * 2^2 - 9 * 2^3) = 20 * 4 - 9 * 8 = 80 - 72 = 8.\)

\(\displaystyle (7 * 2^3 - 10 * 2^4 - 14 * 2^2) = 7 * 8 - 10 * 16 - 14 * 4= 56 - 160 - 56 = - 160.\)

\(\displaystyle 8 - ( - 160) = 8 + 160 = 168.\)

\(\displaystyle 34 * 2^2 - 2 * 2^3 + 10 * 2^4 = 34 * 4 - 2 * 8 + 10 * 16 = 136 - 16 + 160 = 280 \ne 168.\)

 

[lookagain]

Remember that there is an implied 1:
-1(7v³ - 10v⁴ - 14v²)
So each term inside brackets is multiplied by -1:
> > > -7v^{3 +} 10v^{4 +} 14v²

-7v³ + 10v⁴ + 14v²


Denis, please proofread (as needed) after you submit.