Focus on the triangle on the left with the angles (x+7), (3x-18) and (x-9). Add them up and set that result equal to 180, then solve for x
(x+7)+(3x-18)+(x-9) = 180
5x-20 = 180
5x-20+20 = 180+20.... add 20 to both sides
5x = 200
5x/5 = 200/5 .... divide both sides by 5
x = 40
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Repeat a similar set of steps for the triangle on the right. We'll plug in x = 40 and use it to find the value of y
(x+21)+(x+17)+(y) = 180
(40+21)+(40+17)+(y) = 180 .... replace every x with 40
118+y = 180
118+y-118 = 180-118 ... subtract 118 from both sides
y = 62
Final Answer: 62