Page 666 - Algebra 1

SOLUTION
Write the inequality that models the situation. cost of games plus cost of food is no more than 12
2x + 3y ≤ 12 Solve the inequality for y.
2x + 3y ≤ 12
3y ≤ -2x + 12 Subtract 2x from both sides.
y ≤ -_2 x + 4 Divide all three terms by 3 and simplify. 3
Graph the solutions.
Since Kia cannot buy a negative amount of
games and food, use only Quadrant I. Graph
t h e b o u n d a r y l i n e y = - _2 x + 4 . U s e a s o l i d
8 6 4
Caution
The graph of an inequality will represent all of the solutions of the inequality, but only selected points on the graph may represent solutions of the word problem.
y
x
line for ≤.
3
Shade below the line. Kia must buy whole
numbers of games and food items. All the 2
points on or below the line with whole-number coordinates are the different combinations of games and food Kia can buy.
0 2 4 6 8
Lesson Practice
Determine if each ordered pair is a solution of the given inequality.
(Ex 1)
a. (2, 6); y > 3x - 2
b. (4, 1); y < -4x + 1
c. (-6, 2); y ≤ 5
Graph each inequality.
(Ex 2)
d. 4x+5y≥-10
e. x < 6
Graph each inequality using a graphing calculator.
(Ex 3)
f. 4x+2y≤6
g. y>2x+6
Write an inequality for the region graphed on each coordinate plane.
(Ex 4)
h. i.
O
y
y
8
8
4
x
O
x
-8
-4
8
-8
-4
4
8
-4
-4
-8
-8
Lesson 97 651