Question 1134167
y=1-x
substitute
x^2+(1-x)^2=4
x^2+1-2x+x^2=4
2x^2-2x-3=0
x=(1/4)(2+/- sqrt (4+24))
=(1/4)(2+/-2 sqrt (7)
or 0.5+/-0.5 sqrt (7)
numerically 1.82 and -0.82 for x
y=-0.82 and 3.15
(1.82, -0.82) and (-0.82, 1.82)
{{{graph(300,300,-5,5,-5,5,1-x,sqrt(4-x^2),-sqrt(4-x^2))}}}