Use Square Roots
x2=81
x=+9 and -9
(x+6)(x+2)=0
x=-6 and x=-2
4x2+16
4(x2+4)
x2-14x+24
(x-12)(x-2)
x2-81
(x+9)(x-9)
3x2-5=295
x=10 and x=-10
(x-3)(x+7)=0
x=3 and x=-7
6x2-8x
2x(3x-4)
x2-5x-66
(x+6)(x-11)
x2-144
(x+12)(x-12)
(x+7)2=144
x=5 and x=-19
(7x+1)(x+8)=0
x=-1/7 and x=-8
9x2-36x+81
9(x2-4x+9)
x2-18x+80
(x-8)(x-10)
9x2-49
(3x+7)(3x-7)
100+(x-2)2=149
x=-5 and x=9
(11x+33)(-17x+19)=0
x=-3 and x=19/17
15x3+9x2-27x
3x(5x2+3x-9)
x2-10x-56
(x+4)(x-14)
36x2-100
(6x+10)(6x-10)
3(x+1)2-75=117
x=7 and x=-9
(-46x-184)(16x-168)=0
x=-4 and x=10.5 or 21/2
28x10+14x7+21x4+35x2
7x2(4x8+2x5+3x2+5)
x2-x-156
(x+12)(x-13)
25x2+121
Not possible