Carcass wrote:
Which of the following could be the equation of a line parallel to the line 5x - 6y = 9?
(A) \(y = -\frac{5}{6} x + 1\)
(B) \(y = \frac{6}{5}x + 1\)
(C) \(y = \frac{5}{6}x + 1\)
(D) \(y = \frac{3}{2}x - 1\)
(E) \(y = \frac{2}{3}x – 1\)
Key concept: Parallel lines have the same slopeSo, let's take the given equation, 5x - 6y = 9, and rewrite it in
slope-intercept form y = mx + b, where m = the line's slope, and b = the line's y-intercept.
Given: 5x - 6y = 9
Subtract 5x from both sides of the equation: -6y = 9 - 5x
Divide both sides of the equation by -6 to get: y = 9/(-6) - 5x/(-6)
Simplify: y = -3/2 + 5x/6
Rearrange:
y = (5/6)x - 3/2This tells us that the line has slope 5/6 (and the line's y-intercept is -3/2).
So, the correct answer will also have slope 5/6
Since all of the answer choices are expressed in slope-intercept form, we can immediately see that answer choice C represents a line with slope 5/6
Answer: C