Page 8 - Focus KSSM SPM 2021 TG4.5 - Maths DLP

Mathematics SPM Chapter 6 Linear Inequalities in Two Variables
(d) y  x + 6 (c) the points that lie in the region below

Left side Right side the straight line satisfy the equation
y  mx + c.
3 -3 + 6
3 = 3 y
y mx + c
Therefore, point (–3, 3) is the solution of linear y mx + c
inequality y  x + 6.
O x
y mx + c
REMEMBER!
2. For the graph of straight line y = h,
The symbol  means less than or equal to. Form 4
(a) the points that lie on the straight line satisfy
the equation y = h.
Form 4
(b) the points that lie in the region above the
Try Questions 2 – 4 in Try This! 6.1
straight line satisfy the equation y  h.
(c) the points that lie in the region below the
Example of HOTS straight line satisfy the equation y  h.
HOTS Question
In a Cartesian plane, there are two points, P and y
Q, and a straight line R. P(3, –5) lies on the straight
line, y = 4 – 3x and point Q(1, 2) lies in the region y h
above the straight line. Both points P and Q are not y h
the solutions of inequality R. Determine the linear
inequality R. O x
y h
Solution:
Point P lies on the straight line y = 4 – 3x and point
Q lies in the region above the straight line y = 4 – 3x. 3. For the graph of straight line x = k,
Points P and Q are not the solution of linear inequality
R. Therefore, linear inequality R is y  4 – 3x. (a) the points that lie on the straight line satisfy
the equation x = k.
Try this HOTS Question (b) the points that lie in the region on the right
On a Certesian plane, there is a straigh line E, of the straight line satisfy the equation
y = 2x + 5 and three points K, L and M. Given that x  k.
point K lies in the region below the straight line E, (c) the points that lie in the region on the left
point L lies on the straight line E and point M lies in of the straight line satisfy the equation
the region above the straight line E. Determine the x  k.
linear inequality E if only point K is the solution.
Answer: y  2x + 5 y

x k
x
O
C Determining the region that satisfies x k
a linear inequality
x k
1. For the graph of straight line y = mx + c,
(a) the points that lie on the straight line satisfy 4. If the boundary of the shaded region is a dashed
line, then the points on the boundary line are
the equation y = mx + c. not included in the region that satisfies the
(b) the points that lie in the region above the inequality given.
straight line satisfy the equation y  mx + c.

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06 Focus SPM Maths F4.indd 88 17/02/2021 5:24 PM