Respuesta :

Answer:

3 is the missing answer.

Step-by-step explanation:

7 * 3 = ( _ * 3) + ( 4 * 3)

21 = ( _ * 3) + 12              -Multiply 4 * 3 and 7 * 3

9 = _ * 3                          -Divide both sides by 3

3 = missing number

7x3=21 4x3=12 21-12=9 9/3 is 3 so the missing number is 3