Answer:
x = 4 ±
Step-by-step explanation:
Given
(x - 12)(x + 4) = 9 ← expand the left side using FOIL
x² - 8x - 48 = 9 ( ad 48 to both sides )
x² - 8x = 57
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(- 4)x + 16 = 57 + 16
(x - 4)² = 73 ( take the square root of both sides )
x - 4 = ± ( add 4 to both sides )
x = 4 ±
Answer:
(x +6)^2 +(y +2)^2 = 72
Step-by-step explanation:
The given points are vertices of a right triangle. The circle circumscribing that triangle (through all 3 vertices) will have its center at the midpoint of the hypotenuse:
((0, 4) +(-12, -8))/2 = (-6, -2)
The equation of a circle with center (h, k) through point (a, b) is ...
(x -h)^2 +(y -k)^2 = (a -h)^2 +(b -k)^2
For center (-6, -2) and point (0, 4), the equation is ...
(x +6)^2 +(y +2)^2 = (0+6)^2 +(4 +2)^2
(x +6)^2 +(y +2)^2 = 72
