SOLUTION: solve -0.4x < -36 Solve How do you solve something like this

Algebra ->  Equations -> SOLUTION: solve -0.4x < -36 Solve How do you solve something like this      Log On


   

Question 238293: solve -0.4x < -36 Solve How do you solve something like this
Found 2 solutions by checkley77, College Student:
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
-0.4x < -36
X>-36/-.4 (NOTE: WHEN DIVIDING BY A NEGATIVE VALUE THE < SIGN CHANGES TO > SIGN.
X>90 ANS.
PROOF:
LET X=91
-.4*91<-36
-36.4<-36

Answer by College Student(505) About Me  (Show Source):
You can put this solution on YOUR website!
When we have an inequality or equality, we need to isolate the variable in order to find its value.
.
When we add or sustract from both sides of the inequality, the inequality symbol remains the same.
However, when we multiply or divide a NEGATIVE value on both sides, the inequality symbol changes direction.
.
It also changes direction if we decide to swap one side for the other.
Here are a few examples:
.
Sum operation:
20%3E-2%2Bk
20%2B2%3Ek
22%3Ek
If you decide to swap sides, then you'd say: k%3C22 to maintain the same result.
================
Negative Multiplication operation:
30%3E-%28p%2F4%29
30%2A%28-4%29%3Cp
-120%3Cp ...same as to say... p%3E-120
Positive Multiplication operation:
30%3Ep%2F4
30%2A4%3Ep
120%3Ep ...same as to say... p%3C120
===============================================
Now, let's work on your problem:
-0.4x%3C-36
In this case, we need to divide by -0.4, so we know the inequality symbol changes direction... and... negative divided by negative yields a positive answer.
x%3E%28-36%29%2F-0.4
x%3E90
Done!