Is the inequality correctly solved by multiplying each fraction by 100?

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In summary, an inequality is a mathematical statement that compares the values of two expressions using symbols such as <, >, ≤, or ≥. To solve an inequality, you need to isolate the variable on one side using inverse operations, but you also need to flip the inequality sign when multiplying or dividing by a negative number. Unlike equations, inequalities represent a range of possible solutions. Inequalities can be graphed on a number line or coordinate plane, with the solution represented by a shaded region. When solving inequalities, it is important to keep track of the direction of the inequality, flip the sign when necessary, and be cautious when dealing with variables.
  • #1
mathdad
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Solve the inequality.

(9/10) < (3x - 1)/-2 < 91/100

Do I start by multiplying each fraction by 100?
 
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  • #2
That would be one reasonable way of starting. As is so often the case, you can, you don't have to. And, since 100 is positive, multiplying by 100 does not change the direction of the inequalities: 90< -50(3x- 1)< 91.

But that "-" in the "-2" is going to cause problems!
 
  • #3
90< -50(3x- 1)< 91

90 < -150x + 50 < 91

90 < -150x < 91 - 50

90 < -150x < 41

-90/150 > x > -41/150

-3/5 > x > -41/150

Correct?
 

1. What is an inequality?

An inequality is a mathematical statement that compares the values of two expressions using symbols such as <, >, ≤, or ≥. The symbol indicates whether the first expression is less than, greater than, less than or equal to, or greater than or equal to the second expression.

2. How do I solve an inequality?

To solve an inequality, you need to isolate the variable (usually represented by x) on one side of the inequality sign. You can do this by using inverse operations, just like solving an equation. However, when multiplying or dividing by a negative number, you need to flip the inequality sign to maintain the correct relationship between the two expressions.

3. What is the difference between solving an equation and solving an inequality?

The main difference is that when solving an inequality, you have to consider the direction of the inequality sign. This is because inequalities represent a range of possible solutions, rather than just one specific solution like equations do.

4. Can I graph an inequality?

Yes, you can graph an inequality on a number line or a coordinate plane. The solution to the inequality will be represented by a shaded region on the graph. If the inequality has a < or > symbol, the circle on the number line or coordinate plane representing the endpoint will be open (not filled in). If the inequality has a ≤ or ≥ symbol, the circle will be closed (filled in).

5. Are there any special rules for solving inequalities?

Yes, there are a few special rules to keep in mind when solving inequalities. These include: flipping the inequality sign when multiplying or dividing by a negative number, keeping track of the direction of the inequality when combining like terms, and being careful when multiplying or dividing by variables or expressions containing variables.

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