Tìm x: (x - 3)^2- 4= 0

1. Tìm x
a,(x-3)^2-4=0
b,(x+4)^2-(x+1)(x-1)=16
c,3(x-1)^2-3x(x-5)=1

2. Tính
a,(x+2)^2
b,(2x+3)^2-(x+1)^2
c,(2x+3y)^2
d,(2x+y^2)^3
e,(x-3)(x^2+3x+9)
f,25+10x+x^2
g,9/25x^4-1/4

3. Tính
a, (x-1)^2
b, x^2+6x+9
c,(x+y)^2+(x-y)^2
d,x^2-y^2
e,(a+b)(a^2-ab+b^2)+(a-b)(a^2+ab+b^2)
f, x^2-6x+10
g, x^2-2x+5
h,4x-x^2+x