9514 1404 393
Answer:
Step 2 is where the error lies.
The solution is x > 6
Explanation:
The rules for solving inequalities are substantially similar to the rules for solving equations. If you perform the same operation on both sides of the comparison, the value of the variable does not change. (The exception is when that operation is an "order-reversing" operation. See comment below.)
Kahal's steps would be expected to be the same ones you would use:
Step 1: 4x -4 > 20 . . . given
Step 2: 4x > 24 . . . add 4 to both sides
Step 3: x > 6 . . . . . divide by 4
We note that our Step 2 is different from Kahal's Step 2. In Step 2 is where his mistake was made. He added 4 to one side and subtracted 4 from the other side.
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Exception (order-reversing operations)
The operation you will usually run across in high-school algebra that will reverse ordering is multiplication (or division) by a negative number. Consider, for example, ...
1 < 2
-1 > -2 . . . . . both sides of the inequality multiplied (or divided) by -1
Notice that the order has been reversed: the larger magnitude number is now "less than".