Sophie was asked to plot the point (8,5). She started at the origin, moved 8 units up and 5 units to the right, and plotted her point. Explain what Sophie did wrong and determine what point she actually plotted.
To plot the point (8,5), start at the origin and move

...

she plotted (8,5)

Step-by-step explanation:

the formula of that is (x,y). you would need to go 8 to the right and 5 units up. sophie mixed up the values.

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this

step-by-step explanation:

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