Answer:
The charge is negative and the amount is 215
Step-by-step explanation:
Electrons are negative
-354
Protons are positive
+139
-354+139
-215
It's been such a long time, but I think (1) should be the addition property since your adding 5 to both sides.
And (2) should be the multiplication property due to multiplying both sides by 2.
The sum of the angles of a quadrilaterals is 360 so 8s=360 s=45
