
$=(a^2-10a)-(b^2+6b) +16$
$=[(a^2-2(5)a+25)-25]-[(b^2+2(3)b+9)-9]+16$
$=(a-5)^2-25-(b+3)^2+9+16$
$=(a-5)^2-(b+3)^2$
What do you need to know?
Answer:
arc BC = 84 degrees
Step-by-step explanation:
notice:
need to find n before finding arc BC
(13n -16) + (7n + 12) + 6n = 360
13n + 7n + 6n - 16 + 12 = 360
26n - 4 = 360
26n = 364
n = 364/26 = 14
so arc BC = 6*14 = 84 degrees
60 minutes=1 hour
360 minutes=6 hours
so 360 minutes/90 minutes
so your answer is 4 hours