28225:25*15+(7140*9-95-212)*7+621-1694-1307+30582+22580=515233
1) 7140
* 9
64240
2) 64240
- 95
64145
3) 64145
- 212
63933
4) 28225/25=1129
-25
32
- 25
72
- 50
225
-225
0
5) 1128
* 15
5640
+1128
16920
6) 63933
* 7
447531
7) 16920
+447531
464451
8) 464451
+ 621
465072
9) 465072
- 1694
463378
10) 463378
- 1307
462071
11)462071
+ 30582
492653
12) 492653
+ 22580
515233
Раскрываю сразу скобки
27х-63+24х-33=27х+24
51х-96=27х+24
51х-27х=24+96
24х=120
х=120/24
х=5
42х-66-13х+78=28х+14
29х+12=28х+14
29х-28х=14-12
х=2
Сложим два уравнения:
x³ + 3x²y + 3xy² + y³ = 27
(x+y)³ = 3³
x + y = 3
x = 3 - y
3(3-y)y² + y³ = 7
9y² - 3y³ + y³ = 7
2y³ - 9y² + 7 = 0
2y²(y-1) - 7y(y-1) - 7(y - 1) = 0
(y-1)(2y² - 7y - 7) = 0
y1 = 1
2y² - 7y - 7 = 0
D = 49 + 56 = 105
y2 = (7 - √105)/4
y3 = (7 + √105)/4
x1 = 2
x2 = 3 - (7 - √105)/4 = (5 + √105)/4
x3 = 3 - (7 + √105)/4 = (5 - √105)/4
Ответ: ((5 - √105)/4; (7 + √105)/4); ((5 + √105)/4; (7 - √105)/4); (2; 1)