Выражаем у через х:у=-х+6
Х^2+(-х+6)^2=20
Х^2+х^2-12х+36=20
2х^2-12х+16=0
х^2-6х+8=0
D=36-32=4
Х=(6+2)/2=4. Х=(6-2)/2=2
У:4+у=6. У=2
2+у=6. У=4
Ответ:(4;2) и (2;4)
A) 3а(2а³-5а²+2)= 6а⁴-15а³+6а
б) (9х+у)(4х-3у)= 36х²+4ху-27ху-3у²= 36х²-23ху-3у²
с) (а+5)(2а-7)= 2а²+10а-7а-35=2а²+3а-35
д) (х-4)(х²+2х-3)= х³-4х²+2х²-8х-3х+12=х³-2х²-11х+12
<span>1) -√3 + i
|</span>-√3 + i| = √(3+1)=2
cos(5π/6) = -√3/2
sin(5π/6) = 1/2
-√3 + i = 2cos(5π/6) + 2i*sin(5π/6)
2) <span>-√3 - i
|</span>-√3 - i| = √(3+1)=2
cos(7π/6) = -√3/2
sin(7π/6) = -1/2
<span>-√3 - i = 2cos(7</span>π/6) + 2i*sin(7π/6)