Cogito
Algebra 1 · Chapter 1 · Lesson 5
No Solution, or Every Solution
When the x disappears, read what is left.
11 problems · about 20 minutes · A-REI.B.3
Figure — use these to answer the problems
Warm Up
Straightforward practice. Get the method working first.
4 problems8x + 2 = 8x + 11. How many solutions?
Answer2x + 5 = 2x + 5. How many solutions? Use 99 for infinitely many.
Answer7x + 1 = 7x + 4. How many solutions?
Answer4x = 4x. How many solutions? Use 99 for infinitely many.
Answer
Build It Up
The same ideas with more to keep track of.
3 problems3x + 2 = 5x + 2. What is x?
AnswerSort each result by what it means.
Write each item under the heading it belongs to: x = 4 · 3 = 8 · 6 = 6
Exactly one solution
No solution
Every number
Two lines with the same slope and different intercepts. How many solutions?
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
4 problems2(x + 4) = 2x + 8. How many solutions? Use 99 for infinitely many.
Answer6x + 3 = 6x − 3. How many solutions?
AnswerThe Contradiction
3x + 2 = 3x + 8. How many solutions?
AnswerThe Identity
5(x + 2) = 5x + 10. Is every number a solution? 1 for yes, 0 for no.
Answer