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Step by step explanation This is how I got the answer to your question and I gave you the solution I hope this helps you out
If you would like to know how many hours will Lena need to work before she can afford to buy the computer, you can calculate this using the following steps:
$900 - $473 = $427
$427 / $7 = 61 hours of yard work
Result: Lena will need to work 61 hours before she can afford to buy the computer.
Answer:
200
Step-by-step explanation:
C = 0.007x² − 2.8x + 100
There are two ways we can find the minimum. The first is by noticing that this is an upwards parabola, so the minimum is at the vertex. For y = ax² + bx + c, the vertex is at x = -b/(2a).
x = -(-2.8) / (2 × 0.007)
x = 200
Alternatively, we can minimize C using calculus. Take the derivative with respect to x and set to 0:
dC/dt = 0.014x − 2.8
0 = 0.014x − 2.8
x = 200
