Answer: x = 9.611 ; or ; x = 9 11/18 .
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Step-by-step explanation:
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All angles of any triangle must add up to 180 degrees.
So, (10x - 4) + (8x + 3) + 91 = 180 ; Solve for "x" ;
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10x - 4 + 8x + 3 + 81 = 180 ;
Combine the "like terms" on the left-hand side of the equation:
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+10x + 8x = 18x ;
- 4 + 3 + 8 = 7 ;
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18x + 7 = 180 ;
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Subtract "7" from each side of the equation:
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18x + 7 - 7 = 180 - 7 ;
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to get:
18x = 173 ;
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Divide EACH side of the equation by "18" ; to isolate "x" on one side of the equation; and to solve for "x" ;
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18x / 18 = 173 / 18 ;
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x = 9.6111111111111111....
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Write as: 9.611 ; or; 9 11/18.
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