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the quadratic curve crosses the x axis at 3,0 and the y intercept is 9. express this in the equation y = ax2 + bx + c

User Souad
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1 Answer

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10 votes

Answer:

y = ax² - (3a + 3)x + 9

Explanation:

The curve passes through 2 points: (3, 0) and (0, 9)

f(3) = 9a + 3b + c = 0

f(0) = 0 + 0 + c = 9

Therefore, c = 9, so plug this into the first equation:

9a + 3b + 9 = 0

We cannot determine a or b but for a given a we find that

b = - 3a - 3 ⇒ -b = 3a + 3

Therefore, we can express the quadratic curve as:

y = ax² - (3a + 3)x + 9

User Miszczu
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