Marcus finds that (3x^2-2y^2+5x)+(4x^2+12y-7x)= 7x^2-10y^2-2x What error did Marcus make?

A: He combined the terms 5x and –7x incorrectly.
B: He combined the terms 3x^2 and 4x^2 incorrectly.
C: He combined the terms –2y^2 and 12y^2 incorrectly.
D: He subtracted the polynomials instead of adding.

Respuesta :

I believe the correct answer from the choices listed above is option C. The error that Marcus made would be that he combined the terms –2y^2 and 12y^2 incorrectly. It should be 10y^2 when combined not -10y^2. Hope this answers the question.

we have

[tex](3x^{2} -2y^{2}+5x)+(4 x^{2}+12y^{2}-7x)[/tex]

Combine like terms

[tex](3x^{2} -2y^{2}+5x)+(4 x^{2}+12y^{2}-7x)\\=(3x^{2}+4x^{2})+(-2y^{2}+12y^{2})+(5x-7x)\\=7x^{2} +10y^{2}-2x[/tex]

therefore

the answer is the option C

He combined the terms [tex]-2y^{2}[/tex] and [tex]12y^{2}[/tex] incorrectly