Math PicnicEvery sheet is a promise

Which value makes it true?, step by step

An equation is a question, and a solution is a number that makes it a true sentence.

Practice Practice sheetNew questions
The question

Which value of x makes 3x − 6 = 9 true?

Try each value and see which one works

3456
x = 33 × 3 − 6= 3
3=9false
x = 43 × 4 − 6= 6
6=9false
x = 53 × 5 − 6= 9
9=9true
x = 5
  1. 3x − 6 = 9 is a sentence, not an instruction. It is true for one of these values and false for the others, and the way to find out is to try them.
  2. Try x = 3. 3 × 3 − 6 = 3. 3 is not 9, so x = 3 does not work.
  3. Try x = 4. 3 × 4 − 6 = 6. 6 is not 9, so x = 4 does not work.
  4. Try x = 5. 3 × 5 − 6 = 9. 9 really is 9, so x = 5 makes it true.
  5. Only one value out of the four turns the sentence into something true, and that is what a solution is.

How it works.

  1. 01

    3x − 6 = 9 is a sentence, not an instruction. It is true for one of these values and false for the others, and the way to find out is to try them.

  2. 02

    Try x = 3. 3 × 3 − 6 = 3. 3 is not 9, so x = 3 does not work.

  3. 03

    Try x = 4. 3 × 4 − 6 = 6. 6 is not 9, so x = 4 does not work.

  4. 04

    Try x = 5. 3 × 5 − 6 = 9. 9 really is 9, so x = 5 makes it true.

  5. 05

    Only one value out of the four turns the sentence into something true, and that is what a solution is.

Pick another skill