a) (x-2)²-x²=12
х²-4х+4-х²=12
-4х+4=12
-4х=12-4
-4х=8
х=8:(-4)
х=-2
c) (x+3)(x-3)-х²=3x
х²-3х+3х-9-х²=3х
-9=3х
х=-9:3
х=-3
a) (x-2)²-x²=12
х²-4х+4-х²=12
-4х+4=12
-4х=12-4
-4х=8
х=8:(-4)
х=-2
c) (x+3)(x-3)-х²=3x
х²-3х+3х-9-х²=3х
-9=3х
х=-9:3
х=-3