(x+1)²=(x+2)²-5
x²+2x+1=x²+4x+4-5
x²+2x+1-x²-4x+1=0
-2x=-2 inmultim cu -1
x=2/2=1
x=1
b)(t+1)²-(t-3)²=(t-4)²-(t+2)²
t²+2t+1-t²+6t-9=t²-8t+16-t²-4t-4
8t-8=-12t+12
8t-8+12t-12=0
20t-20=0
20(t-1)=0
t-1=0
t=1
c)6x(2x+3)-4(x+1)(x-1)=2(2x-1)²-11
12x²+18x-4x²+4=8x²-8x+7-11
8x²+18x+4=8x²-8x-4
8x²+18x+4-8x²+8x+4=0
26x+8=0
2(13x+4)=0
13x+4=0
13x=-4
x=-4/13