Page 150 - Mathematics

5 15
4
y += x −
2 2
Collecting like terms gives,
5 23
y = x −
2 2

2y = 5x − 23
5x − 2y − 23 0=

Therefore, the equation of the straight line is 5x − 2y − 23 0.=
Tanzania Institute of Education

Finding the equation of a straight line given the gradient and x or y-intercepts
Given the gradient and x or y-intercept, the equation of a line can also be obtained
directly by substituting these values in the equation, y = mx + . c

Example 6.21

3
Find the equation of a straight line whose gradient is and its y-intercept
is (0, 3). 2

Solution
3
Given the gradient m = and the y-intercept (0, 3), then substitute (0, 3).
2
From y = mx + , c substitute m = 3 and c = 3 in this equation to obtain
2
3
y = x + 3.
2
Therefore, the equation of the line is y = 3 x + 3.
2

Mathematics Form One A straight line which cuts the x-axis at the point( 2, 0)− has a gradient of 2.−
Example 6.22

Find its equation.

Solution
. Substitute these values into the
2
Given that m = − and x-intercept ( 2, 0)−
equation y =
, c That is,
mx +
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25/10/2024 09:51:57
Mathematics form 1.indd 144 25/10/2024 09:51:57
Mathematics form 1.indd 144