Решите систему уравнений: а)у=2х-5 х^2+у^2=25 б)у=х^2-4х+1 2х+у=4

А)y=2x-5
x^2+y^2=25
x^2+(2x-5)^2=25
x^2+4x^2-20x+25 =25
5x^2-20x = 0
5x^2=20x
x^2=25
x=5
y=5
б)y=x^2-4x+1
  2x+y=4
    2x+x^2-4x+1 = 4
    x^2-2x-3=0
    x1=1
    x2=3
    y1=2
    y2=-2
Вроде как то так)))

A) y=2x–5
x^2+y^2=25
x^2+(2x–5)^2=25
x^2+4x^2–20x+25–25=0
5x^2–20x=0
5x(x–4)=0
5x=0; x–4=0
x1=0; x2=4
y1=–5; y2=3

б) у=х^2–4х+1
2х+у=4; у=4–2х
2х+х^2–4х+1–4=0
х^2–2х–3=0
Д=/4–4•1•(-3)=/16=4
х1=(2+4)/2=3; х2=(2–4)/2=–1
у1=4–2•3=–2; у2=4–2•(-1)=6