Question

verify the commutative law of addition for the following pairs of rational number

1). -5/7 and 3/4​

Answer 1

lets add -5/7 and 3/4 first

LCM of denominators = 28

therefore we get, -20/28 and 21/28

= -20/28 + 21/28

= (-20+21)/28

= 1/28

now by using commutative property of addition, we get :

21/28 + (-20/28)

= (21+(-21))/28

As we know, when signs '+' and '-' come together, it is treated as '-'

therefore, (21-20)/28

= 1/28

hence proved.