36(x-3)+36(x+3)=5(x²-9)
36(х-3+х+3)=5х²-45 72х=5x²-45 5x²-72x-45=0 D=72²+4*5*45=5184+900=6084 √D=78 x1=0.5(72+78)=75 x2=0.5(72-78)= - 3