Three items were bought at a car boot sale. Item A
Mass = 42 grams
Volume = 2 cm
Item B
Mass = 87.5 grams
Volume 5 cm3
Item C
Mass = 147 grams
Volume = 7 cm3
=

The density of platinum is approximately 21 grams per cmº.
Which of the items cannot be platinum?
You must show your working.

Item B

Step-by-step explanation:

A:

density = mas/volume = 42 g / 2 cm^3 = 21 g/cm^3    

This may be platinum.

B.

density = mass/volume = 87.5 g / 5 cm^3 = 17.5 g/cm^3

This cannot be pure platinum.

C.

density = mass/volume = 147 g / 7 cm^3 = 21 g/cm^3

This may be platinum.

Item B

the required function is .

step-by-step explanation:

from the given table it is noticed that the graph passing through (-3,7), (0,4), (3,1) and (8,-4).

it is a linear function because the value of y is decrease by one as the value of x increase by 1.

the slope of the function is

the slope of the function is -1 and the y-intercept is 4.

the slope intercept form is

where, m is slope and b is y-intercept.

therefore the required function is . the graph of this function is shown below.