Question 249546
3|1-4x|+4<=28 
3|1-4x|<=24
|1-4x|<=8
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1-4x<=8
-4x<=7
x>=-7/4 reverse the inequality sign when * or / by a negative number.
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1-4x>=-8 reverse the inequality sign and make the 8 negative.
-4x>=-9
x<=9/4 reverse the inequality sign again.
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Ed
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{{{graph(500,200,-10,10,-10,10,abs(1-4x)<=8)}}}