The area of a square can be modeled by the equation A = 12000 + 400,
where x is the serial number of the square. What is the serial
number of the square with a side length of 100 cm?

pls help

"[because of the emancipation proclamation] the condition of things [became] … unsettled, revolutionary, with nothing clearly defined, neither slave nor slaveholder having any rights which they felt bound mutually to respect … slave property in the state of missouri was almost a dead weight to the owner; he could not sell because there were no buyers."—h.c. bruce, a former slave in missouri what does this excerpt suggest about the effects of the emancipation proclamation? a. it also undermined slavery in the border states despite not being in effect there.b. it caused complete disintegration of southern society in the states that seceded.c. it led to slave owners not even trying to stop their slaves from leaving the farms.d. it prevented riots or chaos as both owners and slaves simply ignored each other.