в) 9/12=х/4

To solve this equation, you can use a cross-multiplication method. Cross-multiplication involves multiplying the numerator of the first fraction by the denominator of the second fraction and vice versa.

In this case, we have:

9/12 = x/4

Cross-multiplying, we get:

9 * 4 = 12 * x

36 = 12x

Dividing both sides by 12 gives:

36/12 = x

3 = x

Therefore, the value of x is 3.