方程x2-2(3x-2)+(x+1)=0的一般形式是 ( )
A:x2-5x+5=0
B:x2+5x+5=0
C:x2+5x-5=0
D:x2+5=0
69-6=____
70+16=____
80+16-40=____
You bought a new computer last week, ______ you?