The problem gives the equation $y = \frac{7}{\sqrt{x}} - 70$. We need to find the value of $y$ when $x = 2.53 \times 10^{-8}$, and express the answer in standard form.

1. Problem Description

The problem gives the equation $y = \frac{7}{\sqrt{x}} - 70$. We need to find the value of $y$ when $x = 2.53 \times 10^{-8}$, and express the answer in standard form.

2. Solution Steps

First, we substitute the given value of $x$ into the equation:

$y = \frac{7}{\sqrt{2.53 \times 10^{-8}}} - 70$

Next, we evaluate the square root:

$\sqrt{2.53 \times 10^{-8}} = \sqrt{2.53} \times \sqrt{10^{-8}} \approx 1.5906 \times 10^{-4}$

Then we substitute this back into the equation for $y$:

$y = \frac{7}{1.5906 \times 10^{-4}} - 70$

Now, we calculate the fraction:

$\frac{7}{1.5906 \times 10^{-4}} \approx 44008.62$

Finally, we subtract 70 from the result:

$y \approx 44008.62 - 70 = 43938.62$

To express this in standard form, we write it as $4.393862 \times 10^4$. Rounding to two decimal places, we get $4.39 \times 10^4$.

3. Final Answer

$4.39 \times 10^4$