Answer:
x = 7
Step-by-step explanation:
The proportion is
14/6 = 21/(3x - 12) Cross Multiply
14*(3x - 12) = 6*21 Remove the brackets and combine
42x - 168 = 126 Add 168 to both sides
42x = 126 + 168
42x = 294 Divide by 42
x = 294/42
