courses › Algebra

Solve for x when x appears once or on both sides.

Pen and paper is fine · no calculator needed why?

Learn first (about 3 minutes)

Opens at level 16.

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Builds on: Expressions & one-step equations (not open yet)

skills · practice stats

From rounds of this course only: box, review and trial answers are left out. Once a skill has 40 tries, it compares your first 20 tries with your last 20.

• Two-step equations par 10 s not tried yet

  worked example

  Solve for x: −2x − 10 = 10

  Answer: -10

  1. Add 10 to both sides: −2x = 20.
  2. Divide by −2: x = −10.

• x on both sides par 16 s not tried yet

  worked example

  Solve for x: −2x − 14 = 7x − 59

  Answer: 5

  1. Take 7x from both sides: −9x − 14 = −59.
  2. Add 14 to both sides: −9x = −45.
  3. Divide by −9: x = 5.

• Equations with brackets par 19 s not tried yet

  worked example

  Solve for x: 2(x + 5) = 4(x − 1)

  Answer: 7

  1. Distribute: 2x + 10 = 4x − 4.
  2. Take 4x from both sides: −2x + 10 = −4.
  3. Take 10 from both sides: −2x = −14.
  4. Divide by −2: x = 7.

• Fixed fee plus rate par 30 s not tried yet

  worked example

  A tool-hire shop charges a $44 delivery fee plus $40 per day for a floor sander. The hire cost $244 in total. For how many days was the sander hired?

  Answer: 5

  1. Fee plus rate times days: 44 + 40d = 244.
  2. Take off the fee: 40d = 244 − 44 = 200.
  3. Divide by 40: d = 5.

rest ladder

Win 3 of your last 4 rounds and the course rests. A win is 90% right, within 2× the round's par. Pass the review when it comes back and the next rest is longer.

1. 1 day
2. 3 days
3. 7 days
4. 14 days
5. 30 days
6. 60 days
7. mastered · every 90 days

your rounds

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