Final answer:
To solve the proportion 7/x + 9 = 21/3, isolate x by multiplying both sides by x. Simplify the equation by simplifying fractions and combining like terms. Divide both sides by the coefficient of x to find the value of x. Round the answer to the nearest hundredth.
Step-by-step explanation:
To solve the proportion 7/x + 9 = 21/3, we need to isolate x on one side of the equation. First, we can simplify both sides of the equation. On the left side, combine the fractions by finding a common denominator, which in this case is 3. This gives us 7(3)/x + 9(3) = 21/3, which simplifies to 21/x + 27 = 21/3. Next, we can further simplify the equation by multiplying both sides by x to eliminate the fraction. This gives us 21 + 27x = 7x. Rearranging the equation to isolate x, subtract 7x from both sides to get 27x - 7x = 21. Simplifying this equation gives us 20x = 21. Finally, divide both sides by 20 to solve for x, which gives us x = 21/20 = 1.05. Rounding this answer to the nearest hundredth gives us 1.05 rounded to 2 decimal places is 1.05. Therefore, the correct answer is A) 5.33.