Download presentation

Presentation is loading. Please wait.

Published byHilary Holland Modified over 3 years ago

1
3.1 Solving 2-step equations

2
3.1 – Solving 2-step Equations Goals / “I can…” Solve 2-step equations Use deductive reasoning

3
3.1 – Solving 2-step Equations When looking at an algebraic equation like x + 7 = 15 we try to figure out how to get x by itself. We must get rid of the +7. To do this, we might say we undo the + 7 or do the opposite of + 7. Either way we could – 7 from both sides. x + 7 = 15 -7 -7 x = 8

4
3.1 – Solving 2-step Equations When looking at an algebraic equation like ½ x = 9 we try to get x by itself. We must get rid of the multiply by ½ by doing the inverse of that which is to multiply by the reciprocal or 2. 2(½ x) = (9)2 x = 18

5
To solve two-step equations, undo the operations by working backwards. Example: Ask yourself, 1.What is the first thing we are doing to x? 2.What is the second thing? Recall the order of operations as you answer these questions. Dividing by 2 Subtracting 3 To undo these steps, do the opposite operations in opposite order.

6
1.Draw “the river” 2.Add 3 to both sides 3.Simplify 4.Clear the fraction -Multiply both sides by 2 5.Simplify 6.Check your answer Use a DO-UNDO chart as a shortcut to answering the questions. In the table, write the opposite operations in the opposite order DO UNDO ÷2 -3 Follow the steps in the ‘undo’ column to isolate the variable. + 3 + 3 = - 4 x = -8 -4 – 3 = -7 +3 · 2 2 · · 2

7
1) Solve 2x - 1 = -3 + 1 + 1 2x = -2 2 2 x = -1 2(-1) - 1 = -3 -2 – 1 = -3 1.Draw “the river” 2.Add 1 to both sides 3.Simplify 4.Divide both sides by 2 5.Simplify 6.Check your answer D U · 2 - 1 + 1 ÷ 2

8
+ 4 + 4 3 · · 3 x = 36 12 – 4 = 8 2) Solve 1.Draw “the river” 2.Add 4 to both sides 3.Simplify 4.Clear the fraction -Multiply both sides by 3 5.Simplify 6.Check your answer D U ÷ 3 - 4 + 4 · 3

9
3) Solve 3y – 1 = 8 1.y = 3 2.y = -3 3.y = 4.y = Answer Now

10
3) Solve d – 4 = 6 + 4 + 4 d = 10 1.Draw “the river” 2.Clear the fraction - Multiply both sides by 2 3.Simplify 4.Add 4 to both sides 5.Simplify 6.Check your answer D U - 4 ÷ 2 · 2 + 4

11
4) Solve 1.d = -7 2.d = -19 3.d = -17 4.d = 17 Answer Now

12
5) Solve -3 -3 a = 35 1.Draw “the river” 2.Subtract 3 from both sides 3.Simplify 4.Clear the fraction – Multiply both sides by -7 5.Simplify 6.Check your answer D U ÷ -7 + 3 - 3 · -7 Do/Undo Chart – This one is tricky! Remember to always use the sign in front of the number.

13
6) Solve 5z + 16 = 51 1.z = -35 2.z = -7 3.z = 35 4.z = 7 Answer Now

14
- 1 - 1 5 · · 5 3x = 15 3 3 x = 5 7) Solve 1.Draw “the river” 2.Subtract 1 from both sides 3.Simplify 4.Clear the fraction - Multiply both sides by 5 5.Simplify 6.Divide both sides by 3 7.Simplify 8.Check your answer D U · 3 ÷ 5 + 1 - 1 · 5 ÷ 3

15
3.1 – Solving 2-step Equations copy A music store sells a copy of a deluxe electric guitar for $295. This is $30 more than 1/3 the cost of the deluxe electric guitar it is modeled after. What is the cost of the deluxe guitar?

Similar presentations

© 2019 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google