Answer:
x² - 20 = 0
Using the quadratic formula

a = 1 b = 0 c = -20
So we have

Hope this helps you.
Answer:
-50
Step-by-step explanation:
b-5 
b-5 = -45 ( collect like terms)
b = -45 + -5
b = -45 -5 b = -50
Answer:
the atoms can have different numbers of valence electrons
Answer:
x=7
Step-by-step explanation:
Answer:
138
Step-by-step explanation:
Hexagon total angle = 720
170+ 277 + 135 = 582
720 - 582 = 138