1-step Equations: + and – 9/23/13
In elementary school, you solved
equations that looked like this:
In Algebra, we just ...
To solve:
Need to get x by itself.
We must “undo” whatever has been
done to the variable.
Do the same to BOTH SIDES of ...
Equations Have to Balance!
Both sides of the = sign must “weigh”
the same!
When you change one side, do the
same to the ...
Examples:
Solve each equation. Check your
answers!
x + 3 = -7 m – 6 = 8
3.4 + a = 0.5
y – 1.3 = -3.9
1/4 = 1/2 + t
-2/5 = x – 1/3
You Try!
Solve each equation. Check your
answers!
x – 9 = -6 1.6 + n = 10.7
1-step Equations: × and ÷ 9/24/13
Just like with adding and
subtracting, we need to “undo” what is
done to x.
Use divisi...
Examples:
Solve each equation:
2x = 8
12.9 = -3.2b
You Try!
Solve each 1-step equation.
-4.2a = 16.6
Applications 9/26/13
How to solve a word problem using a
linear equation:
1. Write a verbal model
2. Define a variable fo...
Common Language:
In a word problem:
“is” means =
“of” means multiply
“per” means multiply
“less than” usually means su...
Example 1
Paula has 3 more dolls than her friend
Briana. If Paula has 10 dolls, write and
solve an equation to find out h...
You Try!
A used book costs $17 less than the
same book new. The used book costs
$9. Write and solve an equation to
find o...
Example 2
The melting point of bromine is of the
melting point of nitrogen. The melting point
of bromine is −7 C. Write a...
You Try!
The melting point of mercury is about
of the melting point of krypton. The
melting point of mercury is −39 C. Wr...
Example 3
John earns $5 per hour mowing
lawns. Write and solve an equation to
find how many hours he must work to
earn $4...
You Try!
If you save at a rate of $15 per month,
how long will it take you to save $135?
Write and solve an equation.
1 1 solving simple equations
1 1 solving simple equations
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1 1 solving simple equations

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1 1 solving simple equations

  1. 1. 1-step Equations: + and – 9/23/13 In elementary school, you solved equations that looked like this: In Algebra, we just use a variable instead of the box! We could rewrite the same equation like this: x + 3 = 5
  2. 2. To solve: Need to get x by itself. We must “undo” whatever has been done to the variable. Do the same to BOTH SIDES of the = sign! Answer should be: x = some number.
  3. 3. Equations Have to Balance! Both sides of the = sign must “weigh” the same! When you change one side, do the same to the other side, so it stays balanced! x + 3 = 7
  4. 4. Examples: Solve each equation. Check your answers! x + 3 = -7 m – 6 = 8
  5. 5. 3.4 + a = 0.5 y – 1.3 = -3.9
  6. 6. 1/4 = 1/2 + t -2/5 = x – 1/3
  7. 7. You Try! Solve each equation. Check your answers! x – 9 = -6 1.6 + n = 10.7
  8. 8. 1-step Equations: × and ÷ 9/24/13 Just like with adding and subtracting, we need to “undo” what is done to x. Use division to “undo” multiplication. Use multiplication to “undo” division. Remember: A fraction bar means divide! Example: says x divided by 3!
  9. 9. Examples: Solve each equation: 2x = 8 12.9 = -3.2b
  10. 10. You Try! Solve each 1-step equation. -4.2a = 16.6
  11. 11. Applications 9/26/13 How to solve a word problem using a linear equation: 1. Write a verbal model 2. Define a variable for the unknown 3. Write an equation 4. Solve 5. Answer the question in sentence form
  12. 12. Common Language: In a word problem: “is” means = “of” means multiply “per” means multiply “less than” usually means subtract “more than” usually means add
  13. 13. Example 1 Paula has 3 more dolls than her friend Briana. If Paula has 10 dolls, write and solve an equation to find out how many dolls Briana has. Let be Paula’s dolls Briana’s dolls + 3= Briana’s dollsb 10 = b + 3
  14. 14. You Try! A used book costs $17 less than the same book new. The used book costs $9. Write and solve an equation to find out how much the new book cost.
  15. 15. Example 2 The melting point of bromine is of the melting point of nitrogen. The melting point of bromine is −7 C. Write and solve an equation to find the melting point of nitrogen. Let be the Melting point of bromine 1/30 Melting point of nitrogen = Melting point of nitrogenn -7 = 1/30 n
  16. 16. You Try! The melting point of mercury is about of the melting point of krypton. The melting point of mercury is −39 C. Write and solve an equation to find the melting point of krypton.
  17. 17. Example 3 John earns $5 per hour mowing lawns. Write and solve an equation to find how many hours he must work to earn $40. Let be the Amount earned $5 # of hours= # of hoursh 40 = 5 h
  18. 18. You Try! If you save at a rate of $15 per month, how long will it take you to save $135? Write and solve an equation.

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