Final answer:
To simplify the complex fraction, multiply the numerators together and multiply the denominators together.
Step-by-step explanation:
To simplify the complex fraction, we can follow the rule of dividing fractions: multiply the first fraction by the reciprocal of the second fraction. So,
25/x^2 / 25/4 = 25/x^2 * 4/25
Next, we can multiply the numerators together and multiply the denominators together:
25 * 4 = 100 and x^2 * 25 = 25x^2
Therefore, the simplified form of the complex fraction is 100/25x^2, which can be further simplified to 4/x^2.