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
