Answer:
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Step-by-step explanation:
If line <em>m</em> and line <em>r</em> are parallel, the two angles must be congruent, because they are alternate interior angles. Notice how the 2 lines and the transversal form a backwards "Z" and the angles are in the inner corners.
So, if the angles are congruent, we can set them equal to each other.
Now, solve for x by isolating the variable. First, move all the constants to one side and the terms with variables to another.
115 is being subtracted and the inverse of subtraction is addition. Add 115 to both sides.
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3x is being added and the inverse of addition is subtraction. Subtract 3x from both sides.
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x is being multiplied by 4. The inverse of multiplication is division. Divide both sides by 4.
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If the lines are parallel, then <u>x=20</u> so the angles are congruent.