Answer:
42
Step-by-step explanation:
For the proportion ...
[tex]\dfrac{2}{7}=\dfrac{12}{x}[/tex]
Form the "cross products" by multiplying both sides of the equation by 7x (the product of the denominators. This gives you ...
[tex]7x\cdot\dfrac{2}{7}=7x\cdot\dfrac{12}{x}\\\\2\cdot x=7\cdot 12\qquad\text{each numerator $\times$ the opposite denominator}\\\\2x=84[/tex]
After you have formed the "cross products", divide by the coefficient of x:
x = 84/2 = 42
The value of x is 42.
