We know that AC=8x-20 and B is the mid-point of AC
⇒ AB = BC = 
⇒ BC =
⇒ BC = 4x-10
uve prob moved bc its apex but i think either a or c
2x^2 + 16x + 34 = 0
x^2 + 8x + 17 = 0
x^2 + 8x + 16 = -17 + 16 = -1
(x + 4)^2 = -1
x + 4 = sqrt(-1) = ±i
x = -4 <span>±</span> i
The slope of the line is 2/3, so the angle is arctan(2/3) ≈ 33.69°.