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Question
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While playing in a garden, Tanya saw a honeycomb and asked her mother what it was. Her mother replied that it is a honeycomb made by honey bees to store honey. Also, she told her that the shape of the honeycomb formed is a mathematical structure. The mathematical representation of the honeycomb is shown in the graph.
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Based on the above information, answer the following questions.
- How many zeros are there for the polynomial represented by the given graph?
- Write the zeros of the polynomial.
- If the zeros of a polynomial x2 + (p + 1)x + q are 2 and –3 then determine the values of p and g.
- If the square of the difference between the zeros of the polynomial x2 + ax + 45 is 144 then find the value of a.
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Solution
i. The upward-opening parabola cuts the x-axis at two distinct points, so it has two zeros.
ii. The graph cuts the x-axis at x = –7 and x = 7, so these are the zeros of the polynomial.
iii. For x2 + (p + 1)x + q, the sum of zeros is –(p + 1) and the product of zeros is q.
Sum of zeros:
\[2+(-3)=-1=-(p+1)\]
\[p+1=1 \Rightarrow p=0\]
Product of zeros:
\[2\times(-3)=q \Rightarrow q=-6\]
iv. Let the zeros be α and β.
Then α + β = –a and αβ = 45.
\[(\alpha-\beta)^{2}=(\alpha+\beta)^{2}-4\alpha\beta=144\]
\[(-a)^{2}-4(45)=144\]
\[a^{2}-180=144 \Rightarrow a^{2}=324\]
\[a=\pm 18\]

