<PRE><B>Question 117867</B>
If they are supplementary, then angle HDA +angle ADR =180 degrees. So we have the equation: {{{7x-3+2x-6=180}}}




{{{7x-3+2x-6=180}}} Start with the given equation




{{{9x-9=180}}} Combine like terms on the left side



{{{9x=180+9}}}Add 9 to both sides



{{{9x=189}}} Combine like terms on the right side



{{{x=(189)/(9)}}} Divide both sides by 9 to isolate x




{{{x=21}}} Divide


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Answer:

So our answer is {{{x=21}}} </PRE>