someone explain in simple english how to solve inequalities using multiplicatino and division please
This is often confusing.....You just have to remember to "reverse" the inequality sign if you multiply or divide by a negative..
Example
3x > 6 divide both sides by 3
x > 2 and this is true because if x = 4.....then 3(4) > 6 → 12 > 6
But, notice.....what if we had.....
-3x > 6 divide both sides by -3 and reverse the sign
x < -2 the reason for this is that if we kept the sign as ">" we'd have an error
Note the error, here......
-3x > 6 divide by -3 and don't reverse the sign
x > -2 but if x > -2, then 0 should work in the original problem, right???
But -3(0) > 6 = 0 > 6 and this clearly isn't true
So....by reversing the sign we have x < -2 so..... something like -4 should work in the original problem
So.....
-3(-4) > 6 implies that 12 > 6 and that's true......!!!
So....just remember.....multiplying or dividing by a negative means that we have to reverse the signs !!!
This is often confusing.....You just have to remember to "reverse" the inequality sign if you multiply or divide by a negative..
Example
3x > 6 divide both sides by 3
x > 2 and this is true because if x = 4.....then 3(4) > 6 → 12 > 6
But, notice.....what if we had.....
-3x > 6 divide both sides by -3 and reverse the sign
x < -2 the reason for this is that if we kept the sign as ">" we'd have an error
Note the error, here......
-3x > 6 divide by -3 and don't reverse the sign
x > -2 but if x > -2, then 0 should work in the original problem, right???
But -3(0) > 6 = 0 > 6 and this clearly isn't true
So....by reversing the sign we have x < -2 so..... something like -4 should work in the original problem
So.....
-3(-4) > 6 implies that 12 > 6 and that's true......!!!
So....just remember.....multiplying or dividing by a negative means that we have to reverse the signs !!!