Question

How do you evaluate `3x + 15` when x= 12?

Answer 1

Substitute the given value for x into the equation and then solve.

Explanation:

In this case the given x-value is 12, so we put 12 in place of the x giving us the expression `3(12)+15`. Then we solve according to PEMDAS.
Parentheses: in this case, there is nothing to solve inside of the parentheses
Exponents: none
Multiplication: here we multiply `3*12=36`
Addition: now we add `36+15=51`
Subtraction: none

So the final answer is 51.

Answer 2

`3(12) + 15 = 51`

Explanation:

Replace the `x` with the `12`. Multiply the `3` by the `12` and then add `15` to that answer.

Answer 3

`3(12)+15=color(blue)51`

Explanation:

Substitute `12` for `x` in the equation.

`3(12)+15=`

`36+15=`

`51`