Erica has $12 credit on her Cel-Tel phone card. It costs her $1 to make a phone call using her Cel-Tel card. Erica also has $15 credit on her MTT phone card. It costs her $2 to make a phone call using her MTT card. Which system of equations can be solved to find the number of calls, x, that Erica can make and have the same amount of money, y, on both phone cards? yy==−2x+15−x+12
y = - 2 x + 15 y = - x + 12

yy==2x+15−x+15
y = 2 x + 15 y = - x + 15

yy==−2x−15−x−12
y = - 2 x - 15 y = - x - 12

yy==15x−212x−1
y = 15 x - 2 y = 12 x - 1

∠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.