marcus finds that $(3x^{2}-2y^{2}+5x)+(4x^{2}+12y^{2}-7x)=7x^{2}-10y^{2}-2x$. what error did marcus…

marcus finds that $(3x^{2}-2y^{2}+5x)+(4x^{2}+12y^{2}-7x)=7x^{2}-10y^{2}-2x$. what error did marcus make?\nhe combined the terms 5x and -7x incorrectly.\nhe combined the terms $3x^{2}$ and $4x^{2}$ incorrectly.\nhe combined the terms $-2y^{2}$ and $12y^{2}$ incorrectly.\nhe subtracted the polynomials instead of adding.

marcus finds that $(3x^{2}-2y^{2}+5x)+(4x^{2}+12y^{2}-7x)=7x^{2}-10y^{2}-2x$. what error did marcus make?\nhe combined the terms 5x and -7x incorrectly.\nhe combined the terms $3x^{2}$ and $4x^{2}$ incorrectly.\nhe combined the terms $-2y^{2}$ and $12y^{2}$ incorrectly.\nhe subtracted the polynomials instead of adding.

Answer

Explanation:

Step1: Combine like - terms

First, combine the $x^{2}$ terms: $(3x^{2}+4x^{2}) = 7x^{2}$.

Step2: Combine the $y^{2}$ terms

$(-2y^{2}+12y^{2})=10y^{2}$.

Step3: Combine the $x$ terms

$(5x - 7x)=-2x$.

Step4: Find the correct sum

The correct sum is $(3x^{2}-2y^{2}+5x)+(4x^{2}+12y^{2}-7x)=7x^{2}+10y^{2}-2x$. Marcus combined the $y^{2}$ terms incorrectly as he got $- 10y^{2}$ instead of $10y^{2}$.

Answer:

He combined the terms $-2y^{2}$ and $12y^{2}$ incorrectly.