(5-y)^2+17=(y-3)^2. ответ должен быть -8, 25

(5-y)²+17=(y-3)²

25-10y+y²+17=y²-6y+9

y² - сокращаем и получаем:

25-10y+17=-6y+9

42-10y=-6y+9

42-9=10y-6y

33=4y

4y=33  |÷4

y=8,25.

ответ: y=8,25.

X + y = 6 
xy = - 3 

x = 6 - y 
y( 6 - y ) = - 3 
6y - y^2 = - 3 
y^2 - 6y - 3 = 0 
D = 36 + 12 = 48 
√ D = √ 48 = 4 √ 3 
y1 = ( 6 + 4 √ 3 ) : 2 = 3 + 2 √ 3 
y2 = 3 - 2 √ 3 
x = 6 - y
x1 = 6 - ( 3 + 2 √ 3 ) = 3 - 2 √ 3 
x2 = 6 - ( 3 - 2 √ 3 ) = 3 + 2 √ 3 

x^4 = ?
1) ( 3 - 2 √ 3 )^4 = ? 
( 3 - 2 √ 3 )^2 = 9 - 12*3 + 4*3 = 9 - 36 + 12 = - 15 
( 3 - 2 √ 3 )^4 = - 15 * ( - 15 ) = 225 
2) ( 3 + 2 √ 3 )^2 = 9 + 12*3 + 4*3 = 9 + 36 + 12 = 57 
( 3 - 2 √ 3 )^4 = 57 * 57 = 3249 

1) X^4 + y^4 = 225 + 3249 = 3474 
2) X^4 + y^4 = 57 + 225 = 282

X + y = 6 
xy = - 3 

x = 6 - y 
y( 6 - y ) = - 3 
6y - y^2 = - 3 
y^2 - 6y - 3 = 0 
D = 36 + 12 = 48 
√ D = √ 48 = 4 √ 3 
y1 = ( 6 + 4 √ 3 ) : 2 = 3 + 2 √ 3 
y2 = 3 - 2 √ 3 
x = 6 - y
x1 = 6 - ( 3 + 2 √ 3 ) = 3 - 2 √ 3 
x2 = 6 - ( 3 - 2 √ 3 ) = 3 + 2 √ 3 

x^4 = ?
1) ( 3 - 2 √ 3 )^4 = ? 
( 3 - 2 √ 3 )^2 = 9 - 12*3 + 4*3 = 9 - 36 + 12 = - 15 
( 3 - 2 √ 3 )^4 = - 15 * ( - 15 ) = 225 
2) ( 3 + 2 √ 3 )^2 = 9 + 12*3 + 4*3 = 9 + 36 + 12 = 57 
( 3 - 2 √ 3 )^4 = 57 * 57 = 3249 

1) X^4 + y^4 = 225 + 3249 = 3474 
2) X^4 + y^4 = 57 + 225 = 282