Tìm x: ​x^2 + 8x + 7 = 0; 4x^2 + 12x + 5 = 0

Tìm x
x^2+8x+7=0
4x^2+12x+5=0
x^2+10x+16=0
x^2-14x+13=0
(x+3)^2=4
x^3+3x^2+3x+1=0
x^3+6x^2+12x+8=0
x^3+9x^2+27x+27=0