Answer:
Step-by-step explanation:
(a - b)² = a² - 2ab + b²
a = 0.1x
b = 0.2y
(0.1x - 0.2y)²= (0.1x)² - 2*0.1x*0.2y + (0.2y)²
= (0.1)²x² - 0.04xy + (0.2)²y²
= 0.01x² - 0.04xy + 0.04y²
I don't think I need to explain it, the answer is $111
-- The average of 6 numbers is 7.
So those 6 numbers must add up to 42.
-- If one more number results in an average of zero,
the new number must be -42 .
Then all 7 numbers add up to zero.
