Question

When x-y=3 work out the value of y-x

Answer 1

The value of y-x is (-3)

Solution:

Given: The value of x-y=3

To find: The value of y-x

$\bold{x-y=3\rightarrow (1)}$

Let's multiply the equation (1) by (- 1) on both sides,

$\Rightarrow\bold{(x - y)\times(- 1) = 3\times(- 1)}$

$\Rightarrow\bold{-(x-y)=-3}$

On multiplying the sign,

$\Rightarrow\bold{(-x+y)=-3}$

The above equation can also be written as,

$\Rightarrow\bold{y-x=-3\rightarrow \text{(The required equation)}}$

Multiplication of signs:

$\Rightarrow( + )\times( + ) = ( + )$

$\Rightarrow( + )\times( - ) = ( - )$

$\Rightarrow( - )\times( + ) = ( - )$

$\Rightarrow( - )\times( - ) = ( + )$

In simpler terms, when we multiply two integers with the same signs, the result is always positive and when we multiply two integers with different signs, the result is always negative.