If all sides have the same length, then this is an equilateral triangle. Therefore, the measures of the angles are the same and amount to 60°.
Therefore we have the equations:
7x - 3 = 60 add 3 to both sides
7x = 63 divide both sides by 7
x = 9
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11y + 5 = 60 subtract 5 from both sides
11y = 55 divide both sides by 11
y = 5
Check:
m∠N = (7x - 3)° → m∠N = (7(9) - 3)° = (63 - 3)° = 60°
m∠M = (11y + 5)° → m∠M = (11(5) + 5)° = (55 + 5)° = 60°
CORRECT :)
Answer: x = 9 and y = 5