write and solve an equation to determine the value of x in each figure

Answer: " x = 21 " ; The equation is: " 3x + 117 = 180 " .
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Explanation:
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3x + 117 = 180 ;

(Since: these 2 angles along a straight line, with values of
3x" and "117" are supplementary because they both make up all the angles on a straight line; thus they are supplementary angles and add up to 180.
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3x + 117 = 180 ; Solve for "x" ;
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Subtract "117" from EACH side of the equation:
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3x + 117 − 117 = 180 − 117 ;
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to get:
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3x = 63 ;
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Now, divide EACH SIDE of the equation by "3"; to isolate "x" on one side of the equation; and to solve for "x" ;
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3x / 3 = 63 / 3 ;
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x = 21 .
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