Something happened when you copy and pasted the question, was it important to the question?
Answer:

Step-by-step explanation:
observe
||a–b+c|| = ||a+b+c||
(a-b+c)² = (a+b+c)²
(a+b+c)² – (a-b+c)² = 0
((a+b+c)+(a-b+c))((a+b+c)–(a-b+c)) = 0
(2a+2c)(2b) = 0
(a+c)b = 0
a•b + c•b = 0
||a||×||b||×cos(π/8) + ||c||×||b||×cos(θ) = 0

Answer:
4x-4
Step-by-step explanation:
x-10+3x+6=4x-4
Hope helps :3
B: nine and one over two ft
Answer:
obtuse 9 acute 10
Step-by-step explanation:
obtuse is under 30 degrese and acute is above