Question

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

Answer 1

7x^2+10y^2-2x is the correct answer, Marcus put -10y INSTEAD of +10y^2

Explanation:

(3x^2-2y^2+5x)+(4x^2+12y^2-7x)

Combine like terms- I'll add x^2 first, then y^2, and then finally x, and it will be in that order.

7x^2+10y^2-2x

Make sure to check your signs are correct, and you wrote down the proper exponents.

Answer 2

He combined the terms –2y2 and 12y2 incorrectly.