A teacher asked the class to solve the equation 3(x + 2) = 21. Robert wrote 3x + 6 = 21 as his first step. Which property did he use?

He used the distributive property

Robert used the distributive property.

Step-by-step explanation:

3(x + 2) = 21 < is the original equation.

3x + 6 = 21   < is Robert's first step.

Distributive property is a property that states that multiplying the constant by the numerical values/variables in the parentheses will equal the same as multiplying the consonant by the values added together.

Robert multiplied 3 times "x" and "2." This is the distributive property.

I hope this helps! :)

the photograph is photographer and- in the process- ourselves.

step-by-step explanation: