Answer:
b = -n/(2-S) -a
Step-by-step explanation:
S = n/2 (a+b)
divide both sides by (a+b)
S/(a+b) = n/2
flip the equation on the left (it is the same equation just negative)
-(a+b)/-S = n/2
divide both sides by -S
-a-b = n/(2-S)
add a to both sides
-b = n/(2-S) +a
flip the sign (multiply/divide by -1)
b = -n/(2-S) -a
