Marcus finds that (3x2-2y2+5x)+(4x2+12y2-7x)=7x2-10y2-2x. What error did Marcus make?
He combined the terms 5x and –7x incorrectly.
He combined the terms 3x2 and 4x2 incorrectly.
He combined the terms –2y2 and 12y2 incorrectly.
He subtracted the polynomials instead of adding.

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Rinkhals Rinkhals · Answer 1 · 2018-12-26T05:17:20+01:00

Given : (3x² - 2y² + 5x) + (4x² + 12y² - 7x)

Rearranging like terms, we get :

⇒ (3x² + 4x²) + (12y² - 2y²) - 7x + 5x

⇒ 7x² + 10y² - 2x

But, Marcus got the Answer as : 7x² - 10y² - 2x

Marcus combined the terms -2y² and 12y² Incorrectly

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codiepienagoya codiepienagoya · Answer 2 · 2021-10-21T11:14:14+02:00

Following are the solution to the given expression:

Given:

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

To find:

Solve equation=?

Solution:

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

Solving the L.H.S part:

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

Solving the R.H.S part:

[tex]\bold{=7x^2-10y^2-2x}[/tex]

Since in this question the [tex]L.H.S \neq R.H.S[/tex] , and when we solve the equation so, except the third choice all were correct.

Therefore, the final answer is " He combined the terms [tex]\bold{-2y^2\ and\ 12y^2}[/tex]incorrectly."

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