Answer:
6
Step-by-step explanation:
We use BODMAS/BIDMAS here.
First, we do 5 × 2, as multiplication comes before subtracting and adding.
5 × 2 = 10
Now we can just add and subtract.
5 - 10 = -5
-5 + 11 = 6
The answer is 42.8
I hope that helps<span />
Sum/difference:
Let
This means that
Now, assume that 
is rational. The sum/difference of two rational numbers is still rational (so 5-x is rational), and the division by 3 doesn't change this. So, you have that the square root of 8 equals a rational number, which is false. The mistake must have been supposing that was rational, which proves that the sum/difference of the two given terms was irrational
Multiplication/division:
The logic is actually the same: if we multiply the two terms we get
if again we assume x to be rational, we have
But if x is rational, so is -x/15, and again we come to a contradiction: we have the square root of 8 on one side, which is irrational, and -x/15 on the other, which is rational. So, again, x must have been irrational. You can prove the same claim for the division in a totally similar fashion.
The circumference is 75.4 :)
B
Step-by-step explanation:
