The number y of new vocabulary words that you learn after x weeks is represented by the equation y=15 number 17 a-c.

ANSWER

QUESTION 17a

We were given the relation, , where y represents the number of new vocabularies learned, and x represents the number of weeks

Draw a horizontal line for number of weeks and a vertical line for number of vocabulary words using a scale of 5 units on both axes.

To graph this equation we need at least three points,

When

, ,

So we plot the point

When

, ,

So we plot the point

When

, ,

So we plot the point

Using a straight edge we draw a straight line through these three points.

The equation of the line is of the form , where is the slope.

This tells us that the 15 new vocabulary words are learned each week.

QUESTION 17 B

To find the number of new vocabulary words learnt after 5 weeks, we plug in in to the equation.

This gives us

Therefore after 5 weeks, you learn 75 new vocabulary words.

QUESTION 17 C

We  find the number of vocabulary words learned after 4 weeks and subtract it from the number of vocabulary words learned after 6 weeks'

To find the number of new vocabulary words learnt after 4 weeks, we plug in in to the equation.

This gives us

Therefore after 4 weeks, you learn 60 new vocabulary words.

To find the number of new vocabulary words learnt after 6 weeks, we plug in in to the equation.

This gives us

Therefore after 6 weeks, you learn 90 new vocabulary words.

We now subtract to get

Therefore you learn 30 more vocabulary words after 6 wees than after 4 weeks.