Answer:
x=10
Explanation:
3x+10=6x-20 Set the angles equal to each other b/c they are alt. int. angles.
-3x -3x Subtract by 3x on both sides to get x by itself
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+10 =3x-20
+20 +20 Add 20 to both sides to get x by itself
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30 =3x
/3 /3 Divide both sides by 3 to get x by itself
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10 =x
x=10 Write x first.