Solve a linear equation one step at a time
Start with 3x + 5 = 20. Subtract 5 from both sides to get 3x = 15, then divide both sides by 3. You get x = 5. Check by substituting 5 into the original equation: 3 × 5 + 5 = 20.
Separate observed results from theoretical probability
If a coin lands heads 12 times in 20 tosses, the experimental proportion is 12 ÷ 20 = 60%. The theoretical probability of heads for a fair coin is still 50% on each toss. When a question gives both a model and recorded results, identify which one it asks about.
Try it yourself
Solve 4x − 7 = 17. How can you check your answer?
Show the answer
Add 7 to both sides to get 4x = 24. Divide by 4 to get x = 6. Substitute 6 into the original equation: 4 × 6 − 7 = 17.