Answer
$C=8x+500$
${{\$}} 3700\quad$ for 400 pairs
${{\$}} 6420\quad$ for 740 pairs.
Work Step by Step
Total cost = (cost per pair)(number of pairs)+(fixed cost)
Let
$C=$ cost in dollars.,
$x=$ number of pairs of jeans manufactured,
Fixed cost = 500
A linear equation:
$C=8x+500$
When $x=400,$
$C=(8)(400)+500={{\$}} 3700$
When $x=740,$
$C=(8)(740)+500={{\$}} 6420$
