Let a = r−{0}, the set of all nonzero real numbers, and consider the following relations on a × a. decide in each case whether r is an equivalence relation, justifying your answers. in the case that r is an equivalence relation, find the equivalence classes. (a) (a, b)r(c, d) if and only if ad = bc

Step-by-step explanation:

Let A = R−{0}, the set of all nonzero real numbers, and consider the following relations on A × A.

Given that (a,b) R (c,d) if

Or (a,b) R (c,d) if determinant

a) Reflexive:

We have (a,b) R (a,b) because ab-ab =0 Hence reflexive

b) Symmetric

(a,b) R (c,d) gives ad-bc =0

Or da-cb =0 or cb-da =0 Hence (c,d) R(a,b). Hence symmetric

∠1≅∠2 by the alternate exterior angles theorem.

step-by-step explanation:

given, a ∥ b and ∠1 ≅ ∠3 .we have to prove that e ∥ f

we know that ∠1≅∠3 and that a || b because they are given. we see that by the alternate exterior angles theorem. therefore, ∠2≅∠3 by the transitive property. so, we can conclude that e || f by the converse alternate exterior angles theorem.

we have to fill the missing statement.

transitivity property states that if a = b and b = c, then a = c.

now, given ∠1≅∠3 and by transitivity property ∠2≅∠3 .

hence, to apply transitivity property one angle must be common which is not in result after applying this property which is ∠1.

the only options in which ∠1 is present are ∠1 and ∠2, ∠1 and ∠4

∠1 and ∠4 is not possible ∵ after applying transitivity we didn't get ∠4.

hence, the missing statement is ∠1≅∠2.

so, ∠1≅∠2 by the alternate exterior angles theorem.

50-38=12

step-by-step explanation: