Simplify and Evaluate Variable Expressions

• 3x + 6

• x + 18

• 9x

• 3x + 18

Answer explanation

3(x+6)

Multiply each term inside the parentheses by 3.

3(x) + 3(6)

3x + 18

• -40x

• -10x + 6

• -10x + 1

Answer explanation

-5(2x + 6)

Multiply each term inside the parentheses by -5.

-5(2x) + (-5)(6)

-10x + -30

-10x - 30

Tags

CCSS.6.EE.A.3

• 8x + 7

• 8x + 8

• 16x

• 32x + 8

Answer explanation

6 + 2(4x + 1)

6 + 2(4x) + 2(1)

6 + 8x + 2

8x + 6 + 2

8x + 8

Tags

CCSS.6.EE.A.3

Tags

CCSS.6.EE.A.3

Tags

CCSS.6.EE.A.3

• 87x + 30

• 28x + 30

• 32x

• 117x

Answer explanation

9(2x + 3x) + 6(5 + 7x)

9(5x) + 6(5) + 6(7x)

45x + 30 + 42x

45x + 42x + 30

87x + 30

Tags

CCSS.6.EE.A.3

Write the simplified variable expression for the PERIMETER of the given rectangle.

• 6x

• 12x

• 3x + 3

• 6x + 6

Answer explanation

Perimeter = total distance around a polygon

P = 2x + 3 + x + 2x + 3 + x

Combine the like terms:

P= 2x + x + 2x + x + 3 + 3

P= 6x + 6

• 36

• 18

• 31

• 66

Answer explanation

To find the value of the perimeter you can use the simplified variable expression 6x + 6 and replace "x" with 5.

6(5) + 6

30 + 6

=36

Another option is to replace ALL "x's" with 5, as shown in picture (bottom rectangle). Then, follow the order of operations to simplify the value.

Tags

CCSS.6.EE.A.2C