So firstly, square root 9a^2 and 49: 
Next, combine like terms, and your answer will be
, or the third option.
Answer:
See Explanation
Step-by-step explanation:
Given

Required
Determine the number of cans for the wall
The dimension of the wall is not given. So, I will use the following assumed values:


First, calculate the area of the wall



If 
Then 
Cross Multiply:



Make x the subject


400 cans using the assume dimensions.
So, all you need to to is, get the original values and follow the same steps
Answer:
Parallel
Step-by-step explanation:
-x+6 slope:-1
X+y=20 slope -1
Hence the answer is parallel