8th grade finals review

A

1

2(5x+4)+3x=3(2x+5)−1

 x=1x = 1x=1

2

What is the slope of a line between the points (–3, 5) and (1, 1)?

Slope = –1

3

Two robots use battery power over time:
Robot X uses 3 kW every hour.
Robot Y uses 5 kW every hour.
Which uses less power over 6 hours, and how much?

 Robot X uses 18 kW (less)

 Robot Y uses 30 kW

4

Find the volume of a cylinder with height 7 in and diameter 4 in.
(Use pi =3.14)

Volume ≈ 87.9 in³

5

Compare volumes:
Cylinder: radius = 3 cm, height = 10 cm
Cone: diameter = 6 cm, height = 10 cm
Which holds more?

Cylinder holds more. 

Volume ≈ 282.6 cm³

Cone ≈ 94.2 cm³

B

1

y=3x+2

2x+y=16

x= 2 

y= 8

2

A bakery sells 4 cookies and 3 cupcakes for $9.60.
6 cookies and 5 cupcakes cost $15.40.

Find the cost of one cookie and one cupcake.

Cookie = $1.00, Cupcake = $1.80

3

Riley earns $2,300 after selling 4 tablets, and $2,800 after selling 6.
What is her commission per tablet?

$250 per tablet

4

Write the equation of the line that goes through 

(–2, 1) and (3, 6)

 y = x+3

C

1

 Input-output pairs: {(–2, 1), (0, 2), (2, 4), (3, 2)}
Is this a function?

No, because the output 2 appears for both inputs 0 and 3.

2

What type of association is this: As time watching TV increases, test scores decrease.

Negative linear association

3

 A student jogs away from school, waits at the park, then returns. Sketch or describe the shape of the distance vs. time graph.

Increase (going away), flat (waiting), then decrease (returning).

4

create a frequency table to identify how many 7th graders are asked if they play sports? 

35 of the 7th graders play sports

6o of the 8th graders do not play sports 

100 students in total play sports 

216 kids are asked in total  

91

5

A triangle has sides 6 cm and 8 cm. What is the hypotenuse?

10 cm