Solve for x in the equation: 3x + 4 = 19.

To solve the equation 3x + 4 = 19, you begin by isolating the term with x on one side of the equation. First, you can subtract 4 from both sides of the equation to eliminate the constant on the left side. Doing this gives you:

3x + 4 - 4 = 19 - 4,

which simplifies to

3x = 15.

Next, to isolate x, you divide both sides of the equation by 3:

3x / 3 = 15 / 3,

which simplifies to

x = 5.

Thus, the correct answer is 5. This solution shows that x has been successfully isolated and calculated, confirming that the answer is correct through step-by-step simplification of the equation.