Graph the equation below by plotting the y-intercept and a second point on the line. Y=3x-3
1 answer:
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Answer:
(6, 9 ) and r = 3
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
Given
x² + y² - 12x - 18y + 108 = 0
Rearrange the x- terms and the y- terms together and subtract 108 from both sides, that is
x² - 12x + y² - 18y = - 108
To obtain standard form use the method of completing the square
add ( half the coefficient of the x and y terms )² to both sides
x² + 2(- 6)x + 36 + y² + 2(- 9)y + 81 = - 108 + 36 + 81
(x - 6)² + (y - 9)² = 9 ← in standard form
with centre = (6, 9 ) and r = = 3
Answer:
y = -⅔x + ²²/₃
Step-by-step explanation:
1. Calculate the slope of EF
Assume E is at (-2, 5) and F is at (1, 3).
m₁ = (y₂ - y₁)/(x₂ - x₁) = (3 - 5)/(1 -(-2)) = -⅔
2. Calculate the slope of the parallel line
m₂ = m₁ = -⅔
3. Calculate its y-intercept
y = mx + b
6 =-⅔(2) + b
Simplify
6 = -⁴/₃ + b
Add ⁴/₃ to each side
b = 6 + ⁴/₃ = ¹⁸/₃ + ⁴/₃ = ²²/₃
The y-intercept is at (0,²²/₃).
4. Write the equation for the line
y = -⅔x + ²²/₃
The diagram shows EF in red. The parallel line in black passes through (2, 6) with a y-intercept at (0,²²/₃).
