Everything Maths Grade 10

SOLUTION

Step 1: Draw a sketch

 6  4  2 2 4 6

 6

 4

 2

2

4

6

P(1;5)

Q(5; 4)

x

y

Step 2: Assign values

Let the coordinates ofPbe(x 1 ;y 1 )and the coordinates ofQbe(x 2 ;y 2 ).

x 1 = 1 y 1 = 5 x 2 = 5 y 2 = 4

Step 3: Write down the general formula of the line

yy 1

xx 1

=

y 2 y 1

x 2 x 1

Step 4: Substitute values and makeythe subject of the equation

y(5)

x(1)

=

4 (5)

5 (1)

y+ 5

x+ 1

=

3

2

2 (y+ 5) = 3 (x+ 1)

2 y+ 10 = 3x+ 3

2 y= 3x 7

y=

3

2

x

7

2

Step 5: Write the final answer

The equation of the straight line isy=^32 x^72.

Chapter 8. Analytical geometry 299