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Illustrative Math - Algebra 1 - Unit 7 - Lesson 13

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Last updated 6 days ago
14 Questions

Noah is solving the equation x{2}+8x+15=3. He begins by rewriting the expression on the left in factored form and writes (x+3)(x+5)=3. He does not know what to do next.

Noah knows that the solutions are x=-2 and x=-6, but is not sure how to get to these values from his equation.


Solve the original equation by completing the square.

Match each quadratic expression given in factored form with an equivalent expression in standard form. One expression in standard form has no match.

-x^{2}+4
x^{2}-81
x^{2}-4
x^{2}-y^{2}

Four students solved the equation x^{2}+255=0. Their work is shown here. Only one student solved it correctly.
Determine which student solved the equation correctly. For each of the incorrect solutions, explain the mistake.

This lesson is from Illustrative Mathematics. Algebra 1, Unit 7, Lesson 13. Internet. Available from https://curriculum.illustrativemathematics.org/HS/teachers/1/7/13/index.html ; accessed 26/July/2021.

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