Easy question will give brainliest and thanks 1) 4x^2 + 8x +4y^2 +16y -13 = 0 Find the center and radius of the circ

Question

Easy question
will give brainliest and thanks

1) 4x^2 + 8x +4y^2 +16y -13 = 0
Find the center and radius of the circle

2) Given three points on a parabola as (0,4) (4,4) (8,12), determine the equation for that parabola.
put in y=ax^2+bx+c to from a system of three linear equations

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Maya 2 weeks 2021-10-01T20:06:40+00:00 1 Answer 0

Answers ( )

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    2021-10-01T20:07:40+00:00

    Answer:

    1) Centre: (-4,-8)

    Radius: sqrt(93)

    2) y = ¼x² – x + 4

    Step-by-step explanation:

    1) 4x² + 8x +4y² +16y -13 = 0

    h = -8/2 = -4

    k = -16/2 = -8

    (-4)² + (-8)² – (-13) = r²

    r² = 93

    r = sqrt(93)

    sqrt: square root

    2) h = (0+4)/2 = 2

    y = a(x – 2)² + k

    4 = a(0-2)² + k

    4 = 4a + k

    k = 4 – 4a

    12 = a(8-2)² + k

    12 = 36a + k

    12 = 36a + 4 – 4a

    8 = 32a

    a = ¼

    k = 4 – 4(¼) = 4 – 1 = 3

    y = ¼(x – 2)² + 3

    y = ¼(x² – 4x + 4) + 3

    y = ¼x² – x + 1 + 3

    y = ¼x² – x + 4

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45:7+7-4:2-5:5*4+35:2 =? ( )