Question

What is the sign of 3 x y 3xy3, x, y when x > 0 x>0x, is greater than, 0 and y < 0 y<0

Answer 1

The sign is negative

Explanation:

Given

`Expression = 3xy`

`x > 0`

`y<0`

Required

Determine the sign

The expression can be split into 3 factors

`(3) (x) (y)`

If x > 0 then x is positive and If y < 0 then y is negative

So, the expression becomes:

`(+3) (+x) (-y)`

Leave only signs

`(+) (+) (-)`

`+ * + = -`

So, we have:

`(+*+) (-)`

`(+) (-)`

`+ * - = -`

So, we have:

`(+) (-) = -`

Hence, the sign of the expression is negative

Take for instance;

`x = 2`

`y = -4`

The expression would be:

`3 *2 * - 4 =-24` -- negative