Раскройте скобки, 6(х+5)*(х+21)=16(х+3)*(х+9)

6(х+5)*(х+21)=16(х+3)*(х+9)
6(x^2+26x+105)=16(x^2+12x+27)
6x^2+156x+630=16x^2+192x+432
16x^2-6x^2+192x-156x+432-630=0
10x^2+36x-198=0
5x^2+18x-99=0
D=324+1980=2304
x1=-18+48/20=30/20=1,5
x2=-18-48/20=-66/20=-3,3