Răspuns :
y= -x²+4x+5
y= 1+x
1+x =-x²+4x+5
x²-4x+x-5+1=0
x²-3x-4 = 0
(x + 1) • (x - 4)=0
x= -1
x=4
y= 1+x
1+x =-x²+4x+5
x²-4x+x-5+1=0
x²-3x-4 = 0
(x + 1) • (x - 4)=0
x= -1
x=4