Answer:
1, 3, 7, 21
Step-by-step explanation:
1, 3, 7, 21
(The bolded is one factor and the other that is not bolded is another factor)
1 times 21 is 21
3 times 7 is 21
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
