Hello :
all n in N ; n(n+1)(n+2) = 3a a in N or : <span>≡ 0 (mod 3)
1 ) n </span><span>≡ 0 ( mod 3)...(1)
n+1 </span>≡ 1 ( mod 3)...(2)
n+2 ≡ 2 ( mod 3)...(3)
by (1), (2), (3) : n(n+1)(n+2) ≡ 0×1×2 ( mod 3) : ≡ 0 (mod 3)
2) n ≡ 1 ( mod 3)...(1)
n+1 ≡ 2 ( mod 3)...(2)
n+2 ≡ 3 ( mod 3)...(3)
by (1), (2), (3) : n(n+1)(n+2) ≡ 1×2 × 3 ( mod 3) : ≡ 0 (mod 3) , 6≡ 0 (mod)
3) n ≡ 2 ( mod 3)...(1)
n+1 ≡ 3 ( mod 3)...(2)
n+2 ≡ 4 ( mod 3)...(3)
by (1), (2), (3) : n(n+1)(n+2) ≡ 2×3 × 4 ( mod 3) : ≡ 0 (mod 3) , 24≡ 0 (mod3)
3. Look at the picture.
We have the right angle triangle. We know the sum of measures of angles in triangle is equal 180°. Therefore:


4.
Look at the picture.
Use Pythagorean theorem:



5.
TRUE: 1; 2; 4
6.
We find a slope of the line OP:

We have:

Now, we must find the slope of the line perpendicular to the line OP.
We know:

therefore

So. We have the answer! :)
Answer:
y= -1+- i √79/4
Step-by-step explanation: Here is the answer ^^
Answer:
if you need it as improper then 25/12
Step-by-step explanation:
Answer:
1/600, 6/100, 1/1400
Step-by-step explanation: