Question 76074
{{{5-3x>56}}}
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You can operate on inequalities just as you would on an equation with one exception.
That exception is that if you multiply or divide both sides of the inequality by a negative
number, you need to reverse the direction of the inequality.
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In the given problem we need to solve for +x.  To do this we will start by eliminating
the 5 on the left side to leave only the term containing the x on the left side.  Eliminate
the 5 on the left side by subtracting 5 from both sides.  When you do the inequality
becomes:
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{{{ -3x > 56 - 5}}}
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Combine the two numbers that are now on the right side and the inequality is simplified
to:
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{{{ -3x > 51 }}}
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To solve for +x divide both sides by -3.  Because you are dividing both sides by a minus
number you need to reverse the direction of the inequality.  Both of these actions 
(dividing both sides by -3 and reversing the direction of the inequality sign) results in:
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{{{ x < 51/(-3)}}}
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and this simplifies to:
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{{{ x < -17}}}
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This means that on a number line, x can only have values lying to the left of -17.
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Check by letting x be some value less than -17.  For example, let x be -18. If you plug
that value into the original problem in place of x you get:
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{{{5 - 3*(-18) > 56}}}
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This simplifies to:
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{{{5 + 54 > 56}}}
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This is true so when x is less than -17 we have one supporting piece of evidence that it
might be true.  Now let's try letting x = -16.  Substitute this into the original 
problem and you get:
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{{{5 -3*(-16) > 56}}}
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The left side becomes:
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{{{5 + 48 > 56}}}
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You can see that this is NOT true ... so when x is greater than -17 we have an example
that says it will not work.
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Hope that this helps you to understand a little more about how inequalities can be solved.