N; n+1; n+2 - 3 consecutive numbers
n(n + 1) = (n + 2)² - 19 |use a(b + c) = ab + ac and (a + b)² = a² + 2ab + b²
n² + n = n² + 4n + 4 - 19 |subtract n² from both sides
n = 4n - 15 |subtract 4n from both sides
-3n = -15 |divide both sides by (-3)
n = 5
n + 1 = 5 + 1 = 6
n + 2 = 5 + 2 = 7
Answer: 5; 6; 7.
2/5 is equivalent to 4/10 so at the end of February 4/10 was used up
And at the end of January, 3/10 was used
so 4/10 + 3/10 = 7/10
At the end of February, 7/10 of the wood was used
Y= 1/2x + 2 is the correct answer
The mean is unknown because you did not attach any pictures or insert the values
