S.chand Class 8 Maths Solution Chapter 21 Graphs Exercise 21 B

 Exercise 21 B

Question 1

1. Form a table of values showing the coordinates of the points highlighted on each of the graphs given below and hence write the equation showing the relationship between $x$ and $y$.

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2. Copy and complete the table of values for each equation. Hence draw the respective graphs.

(a) y=x+5

x	0	4	7
y

(b) y=2x

x	1	3	6
y

(c) y=2x-3

x	0	3	4	5
y

(d) y=x-5

x	5	8	9	11
y

3. 

(a) Draw the graph of the function y=5x.

(b) Read from the graph, the value of y when

(i) x=5

(ii) x=6

4. Draw a graph to convert miles to kilometres, given 1 mile $=1.6 \mathrm{~km}$. Use the graph to find :

(i) How many kilometres are approximately equal to $4.5$ miles ?

(ii) How many miles are approximately equal to $8 \mathrm{~km}$ ?

5. The following diagram shows the temperatures during a day:

<fig>

(i) Plot the points on a graph and then join the points with straight lines.

(ii) Approximately when did the temperature first reach $30^{\circ} \mathrm{C}$ ? Was the temperature increasing or decreasing at this time ?

(iii) For how long was the temperature above $40^{\circ} \mathrm{C}$ ?

(iv) By how much did the temperature fall between 4 p.m. and 6 p.m. ?