Đáp án:
Giải thích các bước giải:
1. x²+2x+1-y² 2. x²+4x-y²+4
=(x+1)²-y² =x²+4x+4-y²
=(x+y+1).(x+1-y) =(x+2)²-y²
=(x+y+2).(x+2-y)
3.x²-2x-4y²+1 4.x^4+2x-x²+1
=x²-2x+1-4y² =x^4-(x²-2x+1)
=(x-1)²-4y² =x^4-(x-1)²
=(x-1+4y).(x-1-4y) =(x²-x+1).(x²+x-1
5.x²-2xy-z²+y² 6.25-4x²-4xy-y²
=x²-2xy+y²-z² =25-(4x²+4xy+y²)
=(x-y)²-z² =25-(2x+y)²
=(x-y+z).(z-y-z) =(5-2x-y).(5+2x+y)
7.4x²+4x+1-y²-16y-64 8.4a²-4b²-4a+1
=(4x²+4x+1)-(y²+16y+64) =(4a²-4a+1)-4b²
=(2x+1)²-(y-8)² = (2a-1)-4b²
=(2x+1+y+8).(2x+1-y+8) = (2a-1+2b).(2a-1-2b)
=(2x+y+9).(2x-y+7)
9.a²+b²-2ab-z^4 10.4x²-4xy+y²-25
=(a²-2ab+b²)-z^4 =(2x-y)²-25
=(a-b)²-z^4 =(2x-y-5).(2x-y+5)
=(a-b-z²).(a-b+z²)
