1)
36t²-24t+4=(-6t+2)²
2)
(x+1)³-(x-2)³= formula a³-b³=(a-b)(a²+ab+b²)
=(x+1-x+2)[(x+1)²+(x+1)(x-2)+(x-2)²]=
=3(x²+2x+1+x²+x-2x-2+x²-4x+4)=
=3(3x²-3x+3)=
=9(x²-x+1)
3) (x-3)²+5²=(x+1)²
x²-6x+9+25=x²+2x+1
-6x+9+25=2x+1
8x=33
x=33/8
verificare
(x-3)²=(33/8-3)²=(4,125-3)²=1,125²=1,265625 cm²
1,265625 cm² +25=26,265625 cm²
(x+1)²=(33/8+1)²=(4,125+1)²=5,125²=26,265625 cm²