Answer:
D
Step-by-step explanation:
Parallel lines have the same gradient.
A line with a slope of zero is a horizontal line. Although two lines that have a slope of zero will result in two parallel lines, not all parallel lines are horizontal lines. Since the question is asking for which statement <u>must</u> be true, option A is incorrect.
If the slopes of two lines are negative reciprocals, they are perpendicular to each other. This is because the product of the gradients of 2 perpendicular lines is -1. Let the gradient of the first line be A and the other be B.
AB= -1


Thus, option B is incorrect too.
Undefined slopes gives vertical lines. Like option A, if two lines have an undefined slope, they will be parallel to each other. However since parallel lines are nit necessarily vertical lines, option C is also incorrect.
Answer:
y = -7x + 57
Step-by-step explanation:
If the line is parallel, it will have the same slope. So, this line will also have a slope of -7.
Use y = mx + b, plug in the slope and given point, and solve for b:
y = mx + b
-6 = -7(9) + b
-6 = -63 + b
57 = b
Plug in the slope and y intercept into y = mx + b:
y = mx + b
y = -7x + 57
So, the equation is y = -7x + 57
Answer:

Step-by-step explanation:

So, 
= 
Hope this helps :)
Equation is y = 4x + 5
Step-by-step explanation:
- Step 1: Find the slope of the line by m = (y2 - y1)/(x2 - x1). Here y2 = 5, y1 = 9, x1 = 1 and x2 = 0
⇒ m = (5 - 9)/(0 - 1) = 4
- Step 2: Find y-intercept, b. Since the line passes through (0, 5) b = 5
- Step 3: Write the equation in slope-intercept form
⇒ y = 4x + 5