solving equations with decimals 3.6. class announcements warm-up homework check/questions begin...
TRANSCRIPT
Solving Equations with Decimals
3.6
• Class Announcements• Warm-Up• Homework Check/Questions• Begin Section 3.6 Notes• Mini-Break• Conclude Section 3.6 Notes• Exit Slip• Begin Homework
Today’s Schedule
Warm-UpSolve the equations.
3.4
1)3(x1)2(x1. 4)2(a3a)6(82.
Objectives:Solve equations involving decimals.Apply decimal equations to real-life
applications
Vocabulary: exact answer, approximate answer,
percent of
Solving Decimal Equations3.6
Vocabulary: exact answer – use an =
approximate answer – use an ≈
percent of – change the percent to a decimal and multiply
Solving Decimal Equations3.6
20% of 32
.20
x 32 = 6.4
8728 42x -
x ≈ -1.40
Solve the equation. Round to the nearest hundredth.
Example 1 Round for the Final Answer
1. Simplify both sides of the equation.
2. Put variable on 1 side.
3. Do the opposite operation to both sides.
1) Addition/Subtraction
2) Multiplication/Division
4. Check!
Why did we use the ≈ symbol?
1939x 22x
x ≈ -1.12
Example 1 Round for the Final Answer
1. Simplify both sides of the equation.
2. Put variable on 1 side.
3. Do the opposite operation to both sides.
1) Addition/Subtraction
2) Multiplication/Division
4. Check!
Solve the equation. Round to the nearest hundredth.
12.4 0.9-2.4x
x ≈ 5.5
Solve the equation. Round to the nearest tenth.
Example 2 Solve Equations with Decimals
1. Simplify both sides of the equation.
2. Put variable on 1 side.
3. Do the opposite operation to both sides.
1) Addition/Subtraction
2) Multiplication/Division
4. Check!
Star Game
• Each student will receive a magnet• If you get the problem correct on your first try, you can slide your magnet from star to star• DO NOT MOVE ANYONE ELSE’S MAGNET
0.26y 25.34 - 1.13y
y ≈ 29.1
Example 2 Solve Equations with Decimals
1. Simplify both sides of the equation.
2. Put variable on 1 side.
3. Do the opposite operation to both sides.
1) Addition/Subtraction
2) Multiplication/Division
4. Check!
Solve the equation. Round to the nearest tenth.
$4.30
Three people want to share the cost of a pizza equally. The pizza costs $12.89. What should each person pay?
Example 3 Rounding for a Practical Answer
1. Simplify both sides of the equation.
2. Put variable on 1 side.
3. Do the opposite operation to both sides.
1) Addition/Subtraction
2) Multiplication/Division
4. Check!
49.53.4x7.2x4.5
n ≈ 5.1
Example 4 Change Decimals to Integers
1. Simplify both sides of the equation.
2. Put variable on 1 side.
3. Do the opposite operation to both sides.
1) Addition/Subtraction
2) Multiplication/Division
4. Check!
Solve the equation. Round to the nearest tenth.
12.26.1x2.53.7x
n ≈ 4.0
Example 4 Change Decimals to Integers
1. Simplify both sides of the equation.
2. Put variable on 1 side.
3. Do the opposite operation to both sides.
1) Addition/Subtraction
2) Multiplication/Division
4. Check!
Solve the equation. Round to the nearest tenth.
Find the percents of the prices, rounding to the nearest cent.
1.5% of $23.45
2.7% of $62.50
3.11% of $99.99
4.15% of $48.28
$1.17
$4.38
$11.00
$7.24
Example 5 Finding Percents of Numbers
Example 6 Problems with Decimals
You buy a baseball cap at the stadium for a total cost of $35.51. This included the 11% sales tax. What was the original cost of the cap?
$31.99
Exit Slip – Turn in when your done!
Solve the equation. Round result to nearest HUNDREDTH.
1. 53 = 89 + 14m2. 5.31x + 8.25 = 8.54x – 1.19
Algebra 1(A/B)
Tonight’s Homework Assignment:pg. 169 #5-13• Check odd answers in back of book (B.o.B.)• 3.4-3.6 Quiz tomorrow!