Question 208683
Remember  opposite  angles  of  a  parallelogram  are  congruent(equal)
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and,,,if  parallel  lines  cut  by  transversal,,same  side  interior  angles  are  supplementary,,,,,,or  consecutive  angles  of  a  parallelogram  are  supplemental
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a),,,3x-20 = 2(x+5) =2x+10
x=30
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Angles  are  70 degrees
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check,,,3(30)-20=70=2(30+5),,,,,ok
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b),,,4(x+5) + 2(3x+20) =180
4x +20 +6x +40 =180
10x = 120
x=12
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Angles  are,,68,,,112
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4(12+5)=68,,,,2(3*12+20)=112,,,68+112=180,,,,ok
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c),,,2(x+12) + 2(5x+6) = 180
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2x +24 +10x +12 = 180
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12x = 180-36=144
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x=12.
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angles  are,,48,,,,132
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check ,,,48 +132 =180,,,ok