x^2-8x-84=0
x^2-8x=84
x^2-8x+16=84+16
(x-4)^2=100
x-4=10
x=14
x-4=-10
x=-6
x^2+6x-19=0
x^2+6+9=19+9
(x+3)^2=28
x+3=2✓7
x=2✓7 -3
x+3=-2✓7
x=-2✓7 -3
x^2-8x-84=0
x^2-8x=84
x^2-8x+16=84+16
(x-4)^2=100
x-4=10
x=14
x-4=-10
x=-6
x^2+6x-19=0
x^2+6+9=19+9
(x+3)^2=28
x+3=2✓7
x=2✓7 -3
x+3=-2✓7
x=-2✓7 -3