130 likes | 591 Views
Vocabulary. Null/empty set (336): equations that have no solution. No value of the variable results in a true sentence. Represented by ? or { }Identity (336): an equation that is true for every value of the variable. Josh starts walking at a rate of 2 mph. One hour later, his sister Mari
E N D
1. Chapter 7 Lesson 2Solving Equations with Grouping Symbolspgs. 334-338 What you will learn:
Solve equations that involve grouping symbols
Identify equations that have no solution or an infinite number of solutions
2. Vocabulary Null/empty set (336): equations that have no solution. No value of the variable results in a true sentence. Represented by ? or { }
Identity (336): an equation that is true for every value of the variable
3. Josh starts walking at a rate of 2 mph. One hour later, his sister Maria starts on the same path on her bike, riding at 10mph What does t represent?
Why is Maria’s time shown as t-1?
Write an equation that represents the time when Maria catches up to Josh.
4. Example 1: Solve Equations with Parentheses Solve the equation from the previous chart: 2t = 10(t-1)
Write the problem: 2t = 10(t -1)
5. Now check the previous problem. Josh traveled 2 miles ? 5 hour or 2.5 miles
hour 4
Maria traveled 1 hour less than Josh. She traveled: 10 miles ? 1 hour
hour 4 or 2.5 miles
Therefore, Maria caught up to Josh in 1/4 hour or 15 minutes.
6. Another Example 1: Solve Equations with Parentheses Solve: 6(n-3) = 4(n + 2.1)
7. Example 2: Use an Equation to Solve a Problem The perimeter of a rectangle is 20 feet. The width is 4 feet less than the length. Find the dimensions of the rectangle. Then find its area.
8. Since we know the length is 7 ft, now we need to find the width.
9. Example 3: No Solution Solve: 12 - h = -h + 3
10. Example 4: All Numbers as solutionsRemember, an equation that is true for every value of the variable is called an identity. Solve: 3(2g + 4) = 6(g+2)
11. Your Turn!Solve each equation. Check your solution 3(a-5) = 18
3(s+22) = 4(s+12)
4(f+3) + 5 = 17 + 4f
8y - 3 = 5(y - 1) +3y
12. One More! Find the dimension of the rectangle.
P = 460ft
13. PRACTICE IS BY THE DOOR ON YOUR WAY OUT!
QUIZ TOMORROW OVER 7-1 & 7-2