Question

1) 19x2-4x-21=1
2)27x=81

Answer 1

19x²-4x-21=1
19x²-4x-21-1=0
19x²-4x-22=0
D=(-4)²-4·(-22)*19=16+1672=1688=(2√422)²
x1=(-(-4)-2√422)/(2·19)=(2-2√422)/19
x2=(-(-4)+2√422)/(2·19)=(2+2√422)/19

2) 27x=81
    x=81:27
    х=3