A1 = 8 – В 1 день.
An = 218 – Последний день.
Sn = 4859 – Всего селфи.
Формула:
Sn = (A1 + An) * n / 2
4859 = (8 + 218) * n / 2
4859 = (226 / 2) * n
4859 = 113 * n
n = 43
Ответ: 43 дней.
1) 8<span>¹⁶ / 16¹² = 2⁴⁸ / 2⁴⁸ = 1 </span>
<span>
</span>
<span>2) (15<span>а²</span><span>- 10ab)/(<span><span>3ab-2b²) = 5а(3а - 2<span><span>b</span></span>)/(<span><span>b</span></span>·<span><span><span><span>(3а - 2<span><span>b</span></span>)</span></span></span></span>) = 5а/<span><span><span><span><span><span>b</span></span></span></span></span></span></span></span></span></span>
При а= -2,b= -0,1
<span><span><span><span>5а/<span><span><span><span><span><span>b</span></span></span></span></span></span></span></span></span></span> = 5·(-2)/(-0,1) = -10/(-0,1) = 100
<span>
</span>
1) C²-1=(c-1)(c+1)
2) 2)x²-4x+4=(x-2)²=(x-2)(x-2)
3) 3)25y²-4=25y²-2²=(5y-2)(5y+2)
4) 36a²-60ab+25b²=(6-5b)²=(6-5b)(6-5b)