Answer: x = 22
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Work Shown:
The three angles of any triangle always add up 180 degrees.
(angle1) + (angle2) + (angle3) = 180
(3x) + (2x-7) + (4x-11) = 180
(3x+2x+4x)+(-7-11) = 180
9x-18 = 180
9x-18+18 = 180+18 ...... add 18 to both sides
9x = 198
9x/9 = 198/9 .... divide both sides by 9
x = 22
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angle1 = 3x = 3*22 = 66 degrees
angle2 = 2x-7 = 2*22-7 = 37 degrees
angle3 = 4x-11 = 4*22-11 = 77 degrees
66+37+77 = 180, so the answer is confirmed