$\"\"$

The expression is “two fifths of a number equals -24”.

Let n represent the number.

The word “equals” can be represented as “ = ” symbol. $\"\"$

Rewrite the sentence into expression as \ \

$\"\"$

The equation is $\"\"$ $\"\"$

According to multiplication property of equality:

For any number a, b and c, If a = b then ac = bc.

$\"\"$ (Multiply each side by $\"\"$ , the reciprocal of $\"\"$ )

$\"\"$ (Cancel common terms)

$\"\"$ (Multiply: $\"\"$ ) $\"\"$

The number is $\"\"$ .