Question

Solve for x: 3(x+6)=21. A)1 B) 5 C)9 D) 13 ​

Answer 1

A. X=1

Explanation:

To solve this problem, you have to use the distributive property.

Isolate the x from one side of an equation.

Distributive property:

`\sf{A(B+C)=AB+AC}`

First, divide by 3 from both sides of an equation.

`(3(x+6))/(3)=(21)/(3)`

Solve.

21÷3=7

Rewrite the problem down.

x+6=7

Then, subtract by 6 from both sides.

`\sf{x+6-6=7-6}`

Solve.

7-6=1

`\Large\boxed{X=1}`

The solution is x=1, which is our answer.

Answer 2

`\boxed {\boxed {\sf A. \ x=1}}`

Explanation:

We are given the equation:

`3(x+6)=21`

We want to solve for x, so we must isolate the variable by performing inverse operations to both sides of the equation.

(x+6) is being multiplied by 3. The inverse of multiplication is division. Divide both sides of the equation by 3.

`\frac {3(x+6)}{3}=(21)/(3)`

`(x+6)=(21)/(3)`

`(x+6)=7`

Now 6 is being added to x. The inverse operation of addition is subtraction. Subtract 6 from both sides of the equation.

`x+6-6=7-6`

`x=7-6`

`x=1`

We can test our solution by plugging 1 in for x in the original equation.

`3(x+6)=21`

`3(1+6)=21`

`3(7)=21\\21=21`

This checks out (21 is equal to 21) so we know our answer is x=1.