Question

(y+x=3
x2+y2=49)-ето ситема

Answer 1

y=3-x

x^2+(3-x)^2=49

x^2+9-6x+x^2-49=0

2x^2-6x-40=0

D=36-4*2*(-40)= 36+320=356

x1=(6+√356) / 4 = (6+2√89) / 4 = (4+√89)/2

x2=(4-√89)/2

y1=3-(4+√89)/2 = (6-4-√89) / 2 = (2-√89)/2

y2=3-(4-√89)/2=(6-4+√89)/2= (2+√89)/2

Answer 2

откуда в x^2+9-6x+x^2-49=0 появилось 6