y = 4x + 7
This equation is in slope-intercept form, which is y = mx + b, where m is the slope and b is the y-intercept. The slope of this line is 4. Parallel lines have the same slope, thus a line not parallel to this line will not have a slope of 4. Let's check which of these lines does not have a slope of 4.
y - 4x = 9
y = 9 + 4x (add 4x to both sides)
y = 4x + 9 (switch the constant and x-term)
This line has a slope of 4.
4x - y = 8
-y = 8 - 4x (subtract 4x from both sides)
y = -8 + 4x (divide both sides by -1)
y = 4x - 8 (switch the constant and x-term)
This line has a slope of 4.
4y - x = 8
4y = 8 + x (add x to both sides)
y = 8/4 + x/4 (divide both sides by 4)
y = x/4 + 2 (simplify and switch constant and x-term)
This line has a slope of 1/4. It is thus not parallel to the line y = 4x + 7.
Answer:
4y - x = 8
