Question

Найдите 20% от 30% числа n, если n= За^2 — 2а при: 1) а = 20; 2) а = 12; 3) а = 26; 4) а = 2,8.​

Answer 1

Ответ:

n=3a²-2a (Вместо а ставит те самые цифры)

Пошаговое объяснение:

1) 3*(20)²-2*20=3*400-40=1200-40=1160

0,3*1160=348

0,2*348=69,6

2) 3*(12)²-2*12=3*144-24=432-24=408

0,3*408=122,4

0,2*122,4=24,48

3) 3*(26)²-2*26=3*676-52=2028-52=1976

0,3*1976=592,8

0,2*592,8=118,56

4) 3*(28)²-2*2,8=3*7,84-5,6=23,52-5,6=17,92

0,3*17,92=5,376

0,2*5,376=1,0752

Answer 2

To find 20% of 30% of a number n, we need to follow these steps:

1. Calculate 30% of n: 30% of n = (30/100) * n = 0.3 * n
2. Calculate 20% of the result from step 1: 20% of (0.3 * n) = (20/100) * (0.3 * n) = 0.2 * 0.3 * n = 0.06 * n

Now, let's calculate the values for n using the given values of a:

1. a = 20: n = a^2 - 2a n = 20^2 - 2 * 20 n = 400 - 40 n = 360

20% of 30% of n = 0.06 * 360 = 21.6

2. a = 12: n = a^2 - 2a n = 12^2 - 2 * 12 n = 144 - 24 n = 120

20% of 30% of n = 0.06 * 120 = 7.2

3. a = 26: n = a^2 - 2a n = 26^2 - 2 * 26 n = 676 - 52 n = 624

20% of 30% of n = 0.06 * 624 = 37.44

4. a = 2.8: n = a^2 - 2a n = (2.8)^2 - 2 * 2.8 n = 7.84 - 5.6 n = 2.24

20% of 30% of n = 0.06 * 2.24 = 0.1344

So, the values of 20% of 30% of n for the given values of a are as follows:

1. a = 20: 21.6
2. a = 12: 7.2
3. a = 26: 37.44
4. a = 2.8: 0.1344