## PHP

Negate the following Boolean expressions using both approaches.

 `i.   \$b != 4` `ii.  \$a * 3 + 2 > 0` `iii. !(\$a == 5 && \$b >= 7)` `  iv.  \$a == true` `  v.   \$b > 7 && !(\$x > 4)` `  vi.  \$a == 4 || \$b != 2`
###### Solution

First Approach

`i.   !(\$b != 4)`

`ii.  !(\$a * 3 + 2 > 0)`

`iii. !(!(\$a == 5 && \$b >= 7)), `or the equivalent `\$a == 5 and \$b >= 7`

Notice: Two negations result in an affirmative. That is, two NOT operators in a row negate each other.

`iv.  !(\$a == true)`

`v.   !(\$b > 7 && !(\$x > 4))`

`vi.  !(\$a == 4 || \$b != 2)`

Second Approach

`i.   \$b == 4`

`ii.  \$a * 3 + 2 <= 0`

Notice: Please note that arithmetic operators are not negated. Don’t you ever dare replace the plus (+) with a minus (-) operator!

`iii. !(\$a != 5 || \$b < 7)`

Notice: Please note that NOT operator remains intact.

`iv.  \$a != true`

`v.   \$b <= 7 || !(\$x <= 4)`

`vi.  \$a != 4 && \$b == 2`

## Java, C++, C#

Negate the following Boolean expressions using both approaches.

 `i.   b != 4` `ii.  a * 3 + 2 > 0` `iii. !(a == 5 && b >= 7)` `  iv.  a == true` `  v.   b > 7 && !(x > 4)` `  vi.  a == 4 || b != 2`
###### Solution

First Approach

`i.   !(b != 4)`

`ii.  !(a * 3 + 2 > 0)`

`iii. !(!(a == 5 && b >= 7)), `or the equivalent `a == 5 and b >= 7`

Notice: Two negations result in an affirmative. That is, two NOT operators in a row negate each other.

`iv.  !(a == true)`

`v.   !(b > 7 && !(x > 4))`

`vi.  !(a == 4 || b != 2)`

Second Approach

`i.   b == 4`

`ii.  a * 3 + 2 <= 0`

Notice: Please note that arithmetic operators are not negated. Don’t you ever dare replace the plus (+) with a minus (-) operator!

`iii. !(a != 5 || b < 7)`

Notice: Please note that NOT operator remains intact.

`iv.  a != true`

`v.   b <= 7 || !(x <= 4)`

`vi.  a != 4 && b == 2`

## Visual Basic

Negate the following Boolean expressions using both approaches.

 `i.   b <> 4` `ii.  a * 3 + 2 > 0` `iii. Not(a = 5 And b >= 7)` `  iv.  a = True` `  v.   b > 7 And Not(x > 4)` `  vi.  a = 4 Or b <> 2`
###### Solution

First Approach

`i.   Not(b <> 4)`

`ii.  Not(a * 3 + 2 > 0)`

`iii. Not(Not(a = 5 And b >= 7)), `or the equivalent `a = 5 And b >= 7`

Notice: Two negations result in an affirmative. That is, two NOT operators in a row negate each other.

`iv.  Not(a = True)`

`v.   Not(b > 7 And Not(x > 4))`

`vi.  Not(a = 4 Or b <> 2)`

Second Approach

`i.   b = 4`

`ii.  a * 3 + 2 <= 0`

Notice: Please note that arithmetic operators are not negated. Don’t you ever dare replace the plus (+) with a minus (-) operator!

`iii. Not(a <> 5 Or b < 7)`

Notice: Please note that NOT operator remains intact.

`iv.  a != True`

`v.   b <= 7 Or Not(x <= 4)`

`vi.  a <> 4 And b = 2`

## Python

Negate the following Boolean expressions using both approaches.

 `i.   b != 4` `ii.  a * 3 + 2 > 0` `iii. not(a == 5 and b >= 7)` `  iv.  a == true` `  v.   b > 7 and not(x > 4)` `  vi.  a == 4 or b != 2`
###### Solution

First Approach

`i.   not(b != 4)`

`ii.  not(a * 3 + 2 > 0)`

`iii. not(not(a == 5 and b >= 7)), `or the equivalent `a == 5 and b >= 7`

Notice: Two negations result in an affirmative. That is, two NOT operators in a row negate each other.

`iv.  not(a == true)`

`v.   not(b > 7 and not(x > 4))`

`vi.  not(a == 4 or b != 2)`

Second Approach

`i.   b == 4`

`ii.  a * 3 + 2 <= 0`

Notice: Please note that arithmetic operators are not negated. Don’t you ever dare replace the plus (+) with a minus (-) operator!

`iii. not(a != 5 or b < 7)`

Notice: Please note that NOT operator remains intact.

`iv.  a != true`

`v.   b <= 7 or not(x <= 4)`

`vi.  a != 4 and b == 2`