Г) x=y+4
(y+4)² + y²=8.5
y²+8y+16+y²=8.5
2y²+8y+16-8.5=0
2y²+8y+7.5=0
D=64-60=4
y₁ = -8-2 = -2.5 x₁ =-2.5+4= 1.5
4
y₂ = -8+2 = -1.5 x₂ = -1.5+4= 2.5
4
Ответ: (1,5; -2.5)
(2.5; -1.5)
д) x=2y-5
(2y-5)²+4y=10
4y²-20y+25+4y-10=0
4y²-16y+15=0
D=256-240=16
y₁= 16-4 = 1.5 x₁=2*1.5 -5=3-5= -2
8
y₂=16+4 = 2.5 x₂= 2*2.5-5=0
8
Ответ: (-2; 1.5)
(0; 2.5)
е) x=2y-1
5y(2y-1)+y²=16
10y²-5y+y²-16=0
11y²-5y-16=0
D=25+4*11*16=25+704=729=27²
y₁= 5-27 = -1 x₁=2*(-1)-1= -3
22
y₂ = 5+27 = 32 = 16 = 1 ⁵/₁₁ x₂ = 2* (¹⁶/₁₁) -1 = 32-11 = 1 ¹⁰/₁₁
22 22 11 11
Ответ: (-3; -1)
(1 ¹⁰/₁₁; 1 ⁵/₁₁)