Question 257333
Total cost of labor and materials is addition.
So, L(x) + M(x) = T(x). We can express that as
{{{T(x) = 0.3x^2 + 400x + 550 + 0.1x^2 + 50x + 800}}}
combining like terms gets us
{{{T(x) = 0.4x^2 + 450x + 1350}}}