{ x^2+y^2=10} { x+2y=5}

Question

{ x^2+y^2=10} { x+2y=5}

Answer 1

x^2+y^2=10   x=5-2y

(5-2y)^2+y^2=10  x=5-2y

25+4y^2-20y +y^2=10  x=5-2y

5y^2-20y+25=10   x=5-2y

5y^2-20y+15=0 x=5-2y

y^2-4y+3=0

D=16-4*3=4

y1=3

y2=1

x1=5-2*3=-1

x2=5-2*1=3