SOLUTION: the problem is: solve for x and graph on a number line. 5 - 3x > 10x - 8 i came up with X > 1 and when i graphed the problem i started at 1 (i drew the circle NOT shadded

Algebra ->  Algebra  -> Inequalities -> SOLUTION: the problem is: solve for x and graph on a number line. 5 - 3x > 10x - 8 i came up with X > 1 and when i graphed the problem i started at 1 (i drew the circle NOT shadded      Log On

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Question 131317: the problem is: solve for x and graph on a number line.
5 - 3x > 10x - 8
i came up with X > 1
and when i graphed the problem i started at 1 (i drew the circle NOT shadded in) and drew the arrow going in the positive direction.
i can't figure out the right solution for this problem.

Found 2 solutions by checkley71, solver91311:
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
5-3X>10X-8
-3X-10X>-8-5
-13X>-13
X<-13/-13 THE > SIGN CHANGES TO A < SIGN WHEN YOU MULTIPLY OR DIVIDE BY A NEGATIVE (-) VALUE.
X<1 ANSWER.
PROOF:
LET X=.9
5-3*.9>10*.9-8
5-2.7>9-8
2.3>1

Answer by solver91311(12126) About Me  (Show Source):
You can put this solution on YOUR website!
5+-+3x+%3E+10x+-+8

Add -5 to both sides:
-3x%3E10x-13

Add -10x to both sides:
-13x%3E-13

Now divide both sides by -13, but remember that if you multiply or divide both sides of an inequality by a negative number, you have to reverse the sense of the inequality. Look at an example using specific numbers:

2%3C3 is clearly a true statement, but if you multiply both sides by a -1, you get -2 on one side and -3 on the other side, but the 'less than' sign is no longer correct because -2 is actually greater than -3.

So back to your problem:
-13x%3E-13

Divide by -13 and turn the inequality sign around:
x%3C1

So your number line graph should have the open circle at 1, but the arrow needs to go to the left (in the negative direction).

So, let's prove the answer with a couple of examples. 0 is less than 1, so let's substitute 0 for x into the original inequality:

5+-+3%280%29%3E+10%280%29+-+8
5%3E-8, which is a true statement. So far, so good.

2 is greater than 1, so plug in a 2:
5+-+3%282%29+%3E+10%282%29+-+8
5+-+6+%3E+20+-+8
-1%3E12, is most assuredly a false statement. That's a pretty good indication that you have properly defined the solution set interval for your inequality.