Page 141 - Mathematics

(c) From the equation y = − 2x − 3, the -intercepty is obtained by setting
x = 0 in the equation.

From y = − 2x − 3, it implies that,
y = − 2(0) 3−
= − 3 Tanzania Institute of Education

Therefore, the -intercepty is (0, −3).
For x-intercept, set y = 0, that is
0 = − 2x − 3
2x = − 3
− 3
=
2

 3 
Therefore, the x-intercept is − ,0 .


 2 

Example 6.12

Verify that y − 7 3(x= − 3) represents an equation of the straight line passing
through the point (3, 7), hence determine its gradient and y-intercept.

Solution

A line passes through a point if its coordinates satisfies the equation representing
the line.

Thus, substitute the coordinates of (3, 7) in the equation of the line. That is,
7 7 3(3 3)− = −
00=

Therefore, the line with given equation passes through the point (3, 7).

Write the equation in the form of y = mx + , c as follows:
y − 7 3(x= − 3)
y = 3x − Mathematics Form One
2

3
Comparing with y = mx + , c m = and c = − 2.
Therefore, the gradient of the line is 3 and y-intercept is (0, 2).−

135

25/10/2024 09:51:52
Mathematics form 1.indd 135 25/10/2024 09:51:52
Mathematics form 1.indd 135