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# the zeros of a quadratic function are 4 and -3, if the graph of the function has a y int of 48, what is the quadratic?

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- PuzzlingLv 71 month ago
Write down the two zeros:

x = 4

x = -3

Rewrite them as expressions equal to zero:x - 4 = 0

x + 3 = 0

Multiply those expressions together:

y = (x - 4)(x + 3)

You can also multiply that by any non-zero constant and it will have the same zeros:

y = a(x - 4)(x + 3)

Expand that:

y = a(x² - x - 12)

y = ax² - ax - 12a

The y-intercept is found by setting x=0:

y-int = -12a

And you want that equal to 48:

-12a = 48

a = 48/-12

a = -4

Write the final quadratic:

y = -4x² + 4x + 48

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