1) -5²+(-2)⁴ = 25+16=31
2)0,2·5³-0,4·2⁴= 0,2·125-0,4·16= 25-6,4= 19,6
3)3⁴-
![(\frac{2}{5} ) ^{2} <strong></strong>· 6 \frac{1}{4}](https://tex.z-dn.net/?f=%28%5Cfrac%7B2%7D%7B5%7D%20%29%20%5E%7B2%7D%20%3Cstrong%3E%3C%2Fstrong%3E%C2%B7%206%20%5Cfrac%7B1%7D%7B4%7D%20)
= 81-0,4·6,25=81-2,5=78,5
4)8·0,5³+125·0,2²= 8·0,125+0,04=1+5=6
<span>x^2 + 18x + 45 = 0</span>
D = 324 - 180 = 144 = 12^2
x1 = ( - 18 + 12)/2 = - 6/2 = - 3;
x2 = ( - 18 - 12)/2 = - 30/ 2 = - 15
ОТВЕТ:
- 15; - 3
Х - у = πn, n ∈ Z
x + y = π/2 + πk , k ∈Z
сложим:
2х = π(1/2 + n + k) , n,k∈Z
x = π/2(1/2 + m), m ∈Z
х - у = πn, n ∈ Z
x + y = π/2 + πk , k ∈Z
вычтем:
2у = π(1/2 + k - n) , k,n∈Z
y = π/2(1/2 + k -n) , n,k∈Z
Система:
2х+5у=14, |*3
3х-2у=-17 |*2
Система:
6х+15у=42
6х- 4у =-34
19у = 76
у=4
2х+20=14
2х=-6
х=-3
Ответ: (-3; 4)