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I really need help!!!​

I really need help!!!​-example-1

1 Answer

6 votes

Answer:

the third option (a=1, h=0, k=6)

Explanation:

if I understand correctly what your teacher wants from you, then you need find a (the factor of x² in the equation) and the vertex (turnaround point) of the parabola represented by such a quadratic equation.

the vertex point coordinates are called (h, k).

the general form of such an equation equation is

y = ax² + bx + c

so, we have a right away : a=1

now we can make this quickly by using common sense, or a bit more complex by going through mathematical formulas.

the fast, practical way is to know that y=x² is the very basic parabola with its vertex at (0, 0).

y = x² + 6 is simply the same parabola just lifted up (y direction) by 6 units, that makes the vertex (0, 6).

in pure theory, though, we need to find the transformation from the general y = ax² + bx + c form to

y = a(x - h)² + k

we see right away that k = f(h) = h² + 6

y = a(x² - 2xh + h²) + k

a=1

y = x² - 2xh + h² + k = x² - 2xh + h² + h² + 6 =

= x² - 2xh + 2h² + 6

comparing with y = x² + 6

we know that

-2×h = 0

as we have no term with just x.

=> h = 0

2h² + 6 = k

2×0² + 6 = 6 = k

User Jos Van Egmond
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