[tex]\left \{ {{y=x^2-2x-8} \atop {y=4-x}} \right. [/tex]
[tex]x^{2} -2x-8=4-x [/tex]
[tex]x^2-x-12=0 [/tex]
Δ=b²-4ac= (-1)²-4×1×(-12) = 1 + 48 =49
x₁= (-b+√Δ )/2a = (1+7)/2 = 8/2 = 4
x₂= (-b-√Δ )/2a = (1-7)/2 = -6/2 = -3
x₁=4 ==> y₁=4-4=0
x₂=-3==>y₂=4-(-3)=4+3= 7
A(4,0) B(-3,7)