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Why do you flip the inequality sign when you multiply or divide by negative numbers?
Wiki User
∙ 13y ago
because if you didn't the inequality would not be true.
ex. -3x<15
when you solve it WITHOUT CHANGING THE SIGN, you get
x<-5
when you graph that, a possible answer is -7
If you plug that in to the inequality, you get
-3(-7)<15
BUT that's not true! so therefor you need to flip the sign direction
:)
Wiki User
∙ 13y ago
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When you have to reverse the inequality sign?
The usual case is when you multiply or divide an inequality by a negative number.
When you must reverse the inequality sign?
When solving an inequality, you must revers the inequality sign when you multiply (or divide) both sides by a negative number.
Do you switch the sign when you multiply or divide an inequality?
Only when what you're multiplying by/dividing by is negative.
What happens if you multiply or divide an inequality by a negative number?
The inequality sign changes direction. So 2<3 Multiply by -2 and you get -4>-6 (similarly with division).
What happens to the inequality symbol when you subtract a negative number?
The inequality symbol doesn't change direction in this case.Note that that is the same as adding a positive number.Note also that if you MULTIPLY or DIVIDE by a negative number, then you need to change the direction of the inequality symbol.
When you have to reverse the inequality sign?
The usual case is when you multiply or divide an inequality by a negative number.
What must occur in a linear inequality when you divide or multiply by a negative number?
The inequality sign must be flipped.
If you multiply or divide both sides of an inequality by a number you need to reverse the inequality sign?
negative flip
When you solve an inequality and the first step was to multiply or divide by a negative?
yes ... and so?
Do you only flip the inequality when you divide by a negative number?
Yes you do, you also flip the inequality sign if you multiply by a negative # The > and < signs are strictly the "Greater than" and "Less than" signs. The inequality sign is an = with a / stroke through it. If you divide an inequality by -1 it remains an inequality.
When you must reverse the inequality sign?
When solving an inequality, you must revers the inequality sign when you multiply (or divide) both sides by a negative number.
Do you switch the sign when you multiply or divide an inequality?
Only when what you're multiplying by/dividing by is negative.
Do you see any differences from an equation when you add or subtract numbers to both sides of the inequality sign?
No, the process is exactly the same. However, when you multiply or divide, you must be careful: if you multiply or divide by a negative number, the direction of the inequality must be changed, for example: -x + 3 > 15 (multiply by -1) x - 3 < -15
What happens if you multiply or divide an inequality by a negative number?
The inequality sign changes direction. So 2<3 Multiply by -2 and you get -4>-6 (similarly with division).
If you multiply or divide both sides of an inquality by a negative number you need to?
Change the direction of the inequality.
Do you flip the sign of this inequality 8x plus 4y12?
Only when you multiply or divide by a negative number
Why must you flip the inequality symbol when you divide by a negative number?
For the same reason you must flip it when you multiply by a negative number. An example should suffice. 2 < 3 If you multiply by -1, without switching the sign, you get: -2 < -3, which is wrong. Actually, -2 > -3. Look at a number line if you are not sure about this - numbers to the left are less than numbers further to the right. Dividing by a negative number is the same as multiplying by the reciprocal, which in this case is also negative. These signs are strictly the "Greater than" and "Less than" signs. The inequality sign is an = with a / stroke through it. If you divide an inequality by -1 it remains an inequality.
