Big Ideas Math Algebra 1, 2015
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Big Ideas Math Algebra 1, 2015 View details
5. Solving Compound Inequalities
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Exercise 19 Page 85

Split the compound inequality into two separate inequalities.

Solution Set: -10< x < 5
Graph:

And Compound Inequality
Practice makes perfect
We were asked to solve a compound inequality. Let's start by splitting it into separate inequalities. Compound Inequality: -12 < 1/2(4x+16)& < 18 First Inequality: -12 < 1/2(4x+16)& Second Inequality: 1/2(4x+16)&< 18 Notice that compound inequalities written in this way are equivalent to compound inequalities that involve the word and. -12 < 1/2(4x+16) and 1/2(4x+16)< 18

Let's solve the inequalities separately.

First Inequality

Inequalities can be solved in the same way as equations, by performing inverse operations on both sides until the variable is isolated. The only difference is that when you divide or multiply by a negative number, you must flip the inequality sign.
-12<1/2(4x+16)
-24<2*1/2(4x+16)
â–Ľ
Simplify right-hand side
-24<2/2(4x+16)
-24<1(4x+16)
-24<4x+16
-40<4x
-10
This above tells us that -10 is less than all values that satisfy the inequality.
Strict Inequality

Note that the point on -10 is open because it is not included in the solution set.

Second Inequality

Once more, we will solve the inequality by isolating the variable.
1/2(4x+16)<18
2*1/2(4x+16)<36
â–Ľ
Simplify left-hand side
2/2(4x+16)<36
1(4x+16)<36
4x+16 < 36
4x<20
x < 5
We found that all values less than 5 will satisfy the inequality.
Strict Inequality

Note that the point on 5 is open because it is not included in the solution set.

Compound Inequality

The solution set to the compound inequality is the intersection of the solution sets. First Solution Set: - 10 < x& Second Solution Set: x& < 5 Intersecting Solution Set: -10 < x& < 5 Finally, we will graph the solution set to the compound inequality on a number line.

And Compound Inequality