Pearson Algebra 1 Common Core, 2011
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Pearson Algebra 1 Common Core, 2011 View details
6. Compound Inequalities
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Exercise 15 Page 204

Split the compound inequality into two separate inequalities and solve them individually.

Solution: 3.75< x < 8.5
Graph:

Practice makes perfect

We are given a compound inequality. 1/4 < 2x-7/2 < 5 Let's write it as two individual inequalities. This will let us to solve each one separately. 1/4 < 2x-7/2 and 2x-7/2 < 5Now we can solve them separately and later compare their solution sets.

First inequality

We can solve inequalities just like ordinary equations. Notice that by multiplying by 2 on both sides, we can clear the fraction of the variable term and proceed to solve for x.

1/4 < 2x-7/2
2/4 < 2x-7
0.5 < 2x-7
7.5< 2x
7.5/2 < x
3.75 < x
x > 3.75



The first inequality is satisfied by all values greater than 3.75. Note that x cannot equal 3.75.

Second inequality

Now we can solve the second inequality. Again, we will start by multiplying by 2 on both sides to eliminate the fraction.

2x-7/2 < 5
â–¼
Isolate x
2x-7 < 10
2x < 17
x < 17/2
x<8.5

The second inequality is true for all values less than 8.5. Notice that x cannot equal 8.5.

Combining solution sets

Finally, we can combine the obtained solution sets. The first inequality, x>3.75, describes all values greater than 3.75, but not including 3.75. We can represent this by using an open circle at 3.75 and shading the values to the right.

The second inequality, x<8.5, describes all values less than 8.5, not including 8.5. For this, we will use an open circle again, this time at 8.5 and shade the values to the left.

The intersection of these solution sets, 3.75 < x < 8.5, describes the solutions of the compound inequality.