# Toán Lớp 8: 1/ x ² -2x+1-y ² 2/ x ²-2xy+y ²- 9z ² 3/ x ²-4xy +4y ²-z ²+4zt -4t ² 4/ a^4 -ax ³ -ay+xy 5/ x ² +2x+1-y ² 6/ x ² + 2xy +y ²- 4z ² 7/ x

Question

Toán Lớp 8: 1/ x ² -2x+1-y ²
2/ x ²-2xy+y ²- 9z ²
3/ x ²-4xy +4y ²-z ²+4zt -4t ²
4/ a^4 -ax ³ -ay+xy
5/ x ² +2x+1-y ²
6/ x ² + 2xy +y ²- 4z ²
7/ x ²-2xy +y ² -z ² +2zt – t ²
8/ a ³ -ax ² -ay +xy, hướng dẫn giải giúp em bài này ạ, em cảm ơn thầy cô và các bạn nhiều.

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2 tháng 2022-12-22T17:59:21+00:00 2 Answers 0 views 0

TRẢ LỜI ( 2 )

1. 1. x^2-2x+1-y^2
= (x-1)^2-y^2
= (x-1-y)(x-1+y)
2. x^2-2xy+y^2-9z^2
= (x-y)^2-9z^2
= (x-y-3z)(z-y+3z)
3. x^2-4xy+4y^2-z^2+4zt-4t^2
= (x^2-4xy+4y^2)-(z^2-4zt+4t^2)
= (x-2y)^2-(z-2t)^2
= (x-2y-z+2t)(x-2y+z-2t)
4. a^4-ax^3-ay+xy
= x(a^3-x^3)-y(a-x)
= x(a-x)(a^2+ax+x^2)-y(a-x)
= x(a-x)(a^2+ax+x^2-y)
5. x^2+2xy+1-y^2
= (x+1)^2-y^2
= (x+1-y)(x+1+y)
6. x^2+2xy+y^2-4z^2
= (x+y)^2-4z^2
= (x+y-2z)(z+y+2z)
7. x^2-2xy+y^2-z^2+2zt-t^2
= (x^2-2xy+y^2)-(z^2-2zt+t^2)
= (x-y)^2-(z-t)^2
= (x-y-z+t)(x-y+z-t)
8. a^3-ax^2-ay+xy
= a(a^2-x^2)-y(a-x)
= a(a-x)(a+x)+y(a-x)
= a(a-x)(a+x+y)

2. Giải đáp+Lời giải và giải thích chi tiết:
1, x² – 2x + 1 – y²
= (x – 1)² – y²
=(x – 1 – y ).(x – 1 + y)
2, x² – 2xy + y² – 9z²
= (x – y)² – 9z²
= (x – y – 3z).(x – y + 3z)
3, x² – 4xy + 4y² – z² + 4zt – 4t²
= (x² – 4xy + 4y²) – (z² – 4zt + 4t²)
=( x – 2y)² – (z – 2t)²
= (x – 2y – z + 2t).(x – 2y + z – 2t)
4, $a^{4}$ – ax³ – ay + xy
= a(a³ – x³) – (ay – xy)
= a.(a- x).(a² + ax +x²) – y(a – x)
= (a – x).(a³ + a²x + ax² – y)
5, x² + 2x + 1 – y²
= (x + 1)² – y²
= (x + 1 – y).(x + 1 + y)
6, x² + 2xy + y² – 4z²
=(x + y )² – 4z²
= (x + y – 2z).(x + y + 2z)
7, x² – 2xy + y² – z² + 2zt – t²
= (x² – 2xy + y²) – (z² – 2zt + t²)
= (x – y)² – (z – t)²
= (x – y + z – t).(x – y – z  + t)
8, a³ – ax² – ay + xy
= (a³ – ax² ) – (ay – xy)
= a(a² – x²) – y(a – x)
= a(a – x).(a + x) – y(a – x)
=(a – x).(a² + ax – y)