Total capacity = sum of the individual production capacities.
Here,
Total capacity = sum of f(m) = (m + 4)^2 + 100 and g(m) = (m + 12)^2 − 50.
Then f(m) + g(m) = (m + 4)^2 + 100 + (m + 12)^2 − 50.
We must expand the binomial squares in order to combine like terms:
m^2 + 8 m + 16 + 100
+m^2 + 24m + 144 - 50
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Then f(m) + g(m) = 2m^2 + 32m + 160 + 50
f(m) + g(m) = 2m^2 + 32m + 210, where m is the number of
minutes during which the two machines operate.