Question

How do you solve `m/2-7>4`?

Answer 1

`m>22`

Explanation:

`m/2-7>4`

Add 7 to both sides.

`m/2>4+7`

Simplify.

`m/2>11`

Multiply both sides by 2.

`m>11xx2`

Simplify.

`m>22`

Answer 2

`m>22`

Explanation:

Given:`" "m/2-7>4`

You treat this like a normal equation. There is one 'trap' however. If the whole thing is multiplied by a negative number the inequality is turned round the other way.

For example: It is true that `2<4`

Now consider the incorrect calculation of:

`(-1)xx2<(-1)xx4 " implying that " -2<-4` which is false

`-2` is to the right of `-4` on the number line so `-2 > -4`

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Add 7 to both sides giving

`m/2-7+7 >4+7`

`m/2+0>11`

Multiply both sides by 2 giving

`2/2xxm>2xx11`

But `2/2 =1` giving:

`m>22`

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