Step-by-step explanation:
I hope this helps. good luck
Answer:
E
Explanation:
well, process of elimination
Step-by-step explanation:

• y2 → -1
• y1 → 5
• x1 → 4
• x2 → -3

Answer:
B
Step-by-step explanation:
Euler's formula for polyhedra states that
F + V - E = 2
where F is faces, V is vertices and E is edges
Substitute the values given and solve for F, that is
F + 13 - 26 = 2
F - 13 = 2 ( add 13 to both sides )
F = 15 → B
The problem can be solved step by step, if we know certain basic rules of summation. Following rules assume summation limits are identical.




Armed with the above rules, we can split up the summation into simple terms:





=> (a)
f(x)=28n-n^2=> f'(x)=28-2n
=> at f'(x)=0 => x=14
Since f''(x)=-2 <0 therefore f(14) is a maximum
(b)
f(x) is a maximum when n=14
(c)
the maximum value of f(x) is f(14)=196