If they are parallel they will have the same slope , m
So in y = mx + c, if there are two equations which both have the same m value they will be parallel.
If the lines are perpendicular they'll have slopes like this: 1/2 to -2/1 - where they flip and a negative gets added.
In the equations: 10x + 5y = -5 , and y = -2x + 6
We can rearrange 10x + 5y = -5 to be in the form y = mx + c
10x + 5y = -5
5y = -5 - 10x
y = -1 - 2x
y = -2x - 1
Since y = -2x - 1 and y = -2x + 6 both have the same slope of -2 they are parallel!
In order to help explain how you came to your answer. It also helps when marking or reviewing because it's easier to find any mistakes
B) sunlight travels through space - there is nothing to bounce off of until it hits an atmophere
-2° was the initial temperature as it dropped to -5°
-2-5=-7
Hope this helped
