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Algebra (all content)

Course: Algebra (all content) > Unit 10

Lesson 3: Adding & subtracting polynomials: two variables
Math
Algebra (all content)
Polynomial expressions, equations, & functions
Adding & subtracting polynomials: two variables
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Add & subtract polynomials: find the error

CCSS.Math: HSA.APR.A.1
Google Classroom

Problem

Javier tried to subtract two polynomials. His work is shown below:
=(x4−3x2y2+y4)−(−11x4+4x2y2−3y4)=x4−3x2y2+y4+11x4−4x2y2+3y4Step 1=(1−3)x6+(−3+1)y6+(11−4)x6+(−4+3)y6Step 2=−2x6−2y6+7x6−y6Step 3\begin{aligned} &\phantom{=}(x^4-3x^2y^2+y^4)-(-11x^4+4x^2y^2-3y^4) \\\\ &=x^4-3x^2y^2+y^4+11x^4-4x^2y^2+3y^4&\text{Step }1 \\\\ &=(1-3)x^6+(-3+1)y^6 +(11-4)x^6+(-4+3)y^6&\text{Step }2 \\\\ &=-2x^6-2y^6+7x^6-y^6&\text{Step }3 \end{aligned}
At which step did Javier make an error, if at all?
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