tìm x, bt
a,x^2+6x+9=0
b,2x^2+20x+50=0
c,x^2+2x-3=0
d,4x^2+12x+10
vd:a,x^2+14x+49=0
x^2 + 2x.7+7^2=0
(x+7)^2=0
x+7=0
x=-7
b,3x^2+6x-24=0
3.(x^2 +2x-8)=0
x^2+2x-8=0
x^2+2x+1-9=0
x^2+2x.1+12=19
(x+1)^2=9
x+1=3 or c+1=-3
x=3-1 or x=-3-1
x=2 or x=-4
Loga
Sinh Học lớp 12
