So to multiply fractions, you just multiply numerators with numerators and denominators with denominators.
![-(3)/(4)* -(4)/(7)=(12)/(28)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/3y4rfvavkaz1de76vlevl9evt5mtrdaqdj.png)
Next, to simplify the fraction divide the numerator and denominator by their GCF, or greatest common factor. To find their GCF, list the factors of, in this case, 12 and 28 and the greatest one they share is their GCF. In this case, their GCF is 4. Divide 12/28 by 4/4:
![(12)/(28)/ (4)/(4)=(3)/(7)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/sk5zsmopm9lcgpezk7ozdszum3n3b32jma.png)
Since 3 and 7 don't have a GCF greater than 1, 3/7 is your final answer.