What is the value of x?
1 answer:
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Answer:
Step-by-step explanation:
First of all you have to put the zeros into factor form.
y1 = (x + 2)(x - 5)
Notice that the x changes sigh. You say that the zeros are -2 and 5. To get y1 to go to zero, you must make x the opposite sign of what you are given.
Now you have to expand the factored form to get the standard form
y = x^2 + 2x - 5x - 10
y = x^2 - 3x - 10
That's not the right answer.
f(0) = 30 but you have - 10 at the end so you have to multiply the factored form by - 3
-3(f(x)) = -3(x + 2)(x - 5)
-3(f(x)) = -3(x^2 - 3x - 10)
f(x) = -3x^2 + 9x + 30
f(0) = -3(0)^2 + 9(0) + 30
f(0) = 30
The quadratic still has roots of (x +2)(x - 5) but that 3 makes the y intercept = 30.
See the graph below.
