IM 8.4.8 Lesson: How Many Solutions?

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GeoGebra Classroom Activities, IM 6 – 8 Math

Consider the unfinished equation What is the number of solutions the equation would have with the following expression on the right hand side?

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Here are some cards. With your partner, solve each equation. Then, sort the cards into categories.

Describe the defining characteristics of those categories and be prepared to share your reasoning with the class.

For each equation, determine whether it has no solutions, exactly one solution, or is true for all values of x (and has infinitely many solutions).

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Looking back at these three equations...

If an equation has one solution, solve to find the value of that makes the statement true.

For each equation, determine whether it has no solutions, exactly one solution, or is true for all values of x (and has infinitely many solutions).

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Looking back at these three equations...

If an equation has one solution, solve to find the value of x that makes the statement true.

For each equation, determine whether it has no solutions, exactly one solution, or is true for all values of x (and has infinitely many solutions).

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Looking back at these three equations...

If an equation has one solution, solve to find the value of x that makes the statement true.

For each equation, determine whether it has no solutions, exactly one solution, or is true for all values of x (and has infinitely many solutions).

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Looking back at these three equations...

If an equation has one solution, solve to find the value of x that makes the statement true.

For each equation, determine whether it has no solutions, exactly one solution, or is true for all values of x (and has infinitely many solutions).

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Looking back at these three equations...

If an equation has one solution, solve to find the value of x that makes the statement true.

What do you notice about equations with one solution? 

How is this different from equations with no solutions and equations that are true for every ?

Consecutive numbers follow one right after the other. An example of three consecutive numbers is 17, 18, and 19. Another example is -100, -99, -98.

Choose any set of three consecutive numbers. Find their average. What do you notice?

Find the average of another set of three consecutive numbers. What do you notice?

Explain why the thing you noticed must always work, or find a counterexample.

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