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11 votes
11 votes
Completing the square to find the zeros3. a^2+2a-3=0

User Legendmohe
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1 Answer

22 votes
22 votes

Answer:

1 and -3.

Step-by-step explanation:

Given the quadratic polynomial:


a^2+2a-3=0

To use the completing the square method to find the zeros, follow the steps below:

Step 1: Take the constant to the right-hand side.


a^2+2a=3

Step 2: Divide the coefficient of a by 2, square it and add it to both sides.


a^2+2a+(1)^2=3+(1)^2

Step 3: Write the left-hand side as a perfect square.


(a+1)^2=4

Step 4: Take the square root of both sides.


a+1=\pm\sqrt[]{4}

Step 5: Solve for a.


\begin{gathered} a=-1\pm\sqrt[]{4} \\ a=-1\pm2 \\ a=-1+2\text{ or }a=-1-2 \\ a=1\text{ or }a=-3 \end{gathered}

The zeros of the quadratic equation are 1 and -3.

User Akshat Harit
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3.0k points