a) n° + n°+ 42 = 180°
2n + 42 = 180
2n = 180 – 42
2n = 138
n = 138 /2
n° = 69°
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b) ( x+10) + x + ( x+5 ) = 180
x + 10 + x + x + 5 =180
3x + 15 =180
3x =180 – 15
3x = 165
x = 165 /3
x° = 55°
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c) 3q + q + q = 180
5q =180
q = 180/5
q=36°
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d) m + 2m + ( m+10) = 180
m+2m+m+10=180
4m + 10=180
4m = 180 – 10
4m = 170
m=170 / 4
m = 42.5°
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e) y + (y – 30 ) + 90° = 180°
y + y – 30 + 90 = 180
2y + 60 = 180
2y = 180 – 60
2y = 120
y = 120/2
y = 60°
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f) ( t + 10.5 ) + 2t + 90 = 180
t + 10.5 + 2t +90=180
3t + 100.5 = 180
3t = 180 – 100.5
3t = 79.5
t = 79.5/3
t =26.5°
I hope I helped you^_^