So to find y, let's use 7y-4, you first add the 4 to get it away from the y. you are then left with 7y=4 after that you divide 7 from both sides leaving you with y =4/7. you find the decimal answer and that's the answer for y. just plug it in to the rest of the equations after that
When two straight lines intersect, the pairs of nonadjacent angles in opposite posi-tions are known as vertical angles.
If a segment AB is intersected by a transversal labeled t, then ∠1 and ∠3 and ∠2 and ∠4 are vertically angles formed by the transversal t on the segment AB.
Angles ∠1 and ∠2 can be described as adjacent and supplementary angles, so
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Angles ∠3 and ∠2 can be also described as adjacent and supplementary angles, so
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Subtract from the first equation the second equation: