Solving Two-Step Equations!!!

Vocabulary

100

A letter used to represent an unknown number

What is a variable?

200

What is a constant?

What is a fixed value that stands alone without being multiplied or divided by a variable.

300

What is the inverse operation? 

What is a given operation "undos" or "reverses" the other.

400

The number being multiplied by a variable

What is a coefficient?

500

What are the two steps in order to solve 2-step equations?

What is FIRST: Isolate the variable by using the inverse operation. SECOND: Use the inverse operation to remove the coefficient and apply to both sides of the equation.

practice

100

2k+10=16

What is k=3?

200

2a + 11 = 35

What is a=12?

300

13r + 39 = -65

What is r=2?

400

7d + 9.4 = -11.6

What is d=-3?

500

2(2+3x)=16

what is x=2?

practice

100

3a - 5 = 4

What is a=3?

200

5m - 7 = 23

What is m=6?

300

4/5x+5=1

What is x=-25?

400

4j - 71.6 = 28.4

What is j=25?

500

(x+2)/5=2

What is x=8?

Spot the error!

100

1/5m - 4 = 1

1/5m-4+4=1

1/5m=1

m=5

Did not add 4 to both side

200

5x+3=23

5x+3-3=23-3

5x=20

x=100

Multiplied by 5 instead of dividing by 5

300

x/2+5=13

x/2=8

x=4

divided by two

400

2x+1=-5

2x+1+1=-5+1

2x=-4

x=-2

added 1 to both sides

500

10x+20=60

30x=60

x=2

10x and 20 are not like terms 

Real world scenarios

100

Jonathan purchased 120 pieces of candy for Valentne's Day. He gives 2 pleces to each of his friends. When he fishes handing out candy, he has 30 pieces left. How many friends did he glve candy to?

What is

2x+30=120

 x=45?

200

Kevin went to a the store and bought a soccer ball. Joel went to the same store and bought a baseball for $80. The price of the baseball is $10 less than three times the price of the soccer ball. What is the price of the soccer ball? 

what is 80=3x-10

x=$30

300

Netflix charges David $15 per month for a membership, plus a $5 one- time fee for streaming on his phone. How many months will David have his membership for if Netflix changes him $50?

What is 15x+5=50 

x=3?

400

Josselyn is complaining she has too much homework assignments. Hazel has 5 less than 4 times the amount of homework than Josslyn has. If Josselyn has 3 total homework assignments, how many homework assignments does Hazel have?

What is 3=4x-5?

x=2 

500

Jillian brought $50 to spend on rides at the carnival. The rides cost $4 each. How many rides, r, has Jillian paid for if she has only $6 left of her original $50?

What is 6=50-4r ?

r=11