Question 210146
If "A and B are complementary", then {{{A+B=90}}}. 



{{{A+B=90}}} Start with the given equation.



{{{3x-7+11x-1=90}}} Plug in {{{A = 3x-7}}} and {{{B = 11x-1}}}



{{{14x-8=90}}} Combine like terms on the left side.



{{{14x=90+8}}} Add {{{8}}} to both sides.



{{{14x=98}}} Combine like terms on the right side.



{{{x=(98)/(14)}}} Divide both sides by {{{14}}} to isolate {{{x}}}.



{{{x=7}}} Reduce.



----------------------------------------------------------------------


Answer:


So the solution is {{{x=7}}} 



So {{{A=3(7)-7=21-7=14}}} degrees and {{{B=11(7)-1=77-1=76}}} degrees