Answer:
21
Explanation:
First you have to solve for x in the equation 2x + 9 = 23. Cancel 9 on both sides. You cancel 9 by subtracting 9 on the left side and on the right side:
23 - 9 = 14.
Now, you have 2x = 14. To isolate the variable, divide by 2 to cancel out 2.
14 / 2 = 7.
This will give you x = 7. Now that you know what x equals, you can substitute x in 3x. This would make it 3(7), or in other words 3 x 7.
3 x 7 = 21.
This means that 3x would be equal to 21. Hope it helps!