Evaluating Expressions with Unknown Variables

The video tutorial covers evaluating expressions with unknown variables. It begins with an example where the expression 3x + 3y + 3z equals 1, and the task is to find the value of 12x + 12y + 12z. The instructor demonstrates factoring and simplifying the expression to find the solution. A second example is presented with 3a + 5b = 2, asking for the value of 15a + 15b. The instructor explains the limitations in solving this problem due to insufficient information. The tutorial concludes with a summary of the concepts covered.

What is the initial expression given in the problem?

• 15a + 15b = 2

• 3x + 3y + 3z = 1

• 3a + 5b = 2

• 12x + 12y + 12z = 1

Tags

CCSS.7.EE.A.1

How can the expression 12x + 12y + 12z be rewritten?

• 5 times (a + b)

• 3 times (x + y + z)

• 15 times (a + b)

• 12 times (x + y + z)

What is the value of x + y + z derived from the first equation?

• 1

• 3

• 4

• 1/3

Tags

CCSS.6.EE.A.2C

What is the final value of 12x + 12y + 12z?

• 4

• 1

• 12

• 3

What is the new expression introduced in the second problem?

• 3a + 5b = 2

• 3x + 3y + 3z = 1

• 12x + 12y + 12z = 1

• 15a + 15b = 2

Tags

CCSS.7.EE.A.1

What expression are we trying to find in the second problem?

• 15a + 15b

• 3x + 3y + 3z

• 3a + 5b

• 12x + 12y + 12z

Tags

CCSS.8.EE.C.8B

Why can't we solve for a + b in the second problem?

• The equation is incorrect

• The constants are too large

• The variables are undefined

• Not enough information is provided

Tags

CCSS.7.EE.A.1

What happens when you try to factor out a 3 in the second problem?

• You get 3 times a + 5/3b

• You get 3 times a + b

• You get 5 times a + b

• You get 5 times a + 3/5b

Tags

CCSS.7.EE.A.1

What is the result of factoring out a 5 in the second problem?

• 3 times a + b

• 5 times 3/5a + b

• 5 times a + b

• 3 times a + 5/3b

Tags

CCSS.8.EE.C.7B

What is the key takeaway from the second problem?

• Not all problems have enough information to be solved

• All expressions can be simplified

• Equations with variables are unsolvable

• Factoring always provides a solution

Tags

CCSS.8.EE.C.7B