Bài `4`
`1, 2y(x+2)-3x-6`
`=2y(x+2) -(3x+6)`
`=2y(x+2) -3(x+2)`
`=(x+2)(2y-3)`
`2, 3(x+4) -x^2-4x`
`=3(x+4)-(x^2+4x)`
`=3(x+4) -x(x+4)`
`=(x+3)(3-x)`
`3, 2(x+5) -x^2-5x`
`=2(x+5)-(x^2+5x)`
`=2(x+5)-x(x+5)`
`=(x+5)(2-x)`
`4, x^2 +6x-3(x+6)`
`= (x^2+6x) -3(x+6)`
`=x(x+6)-3(x+6)`
`=(x+6)(x-3)`
`5, x(x+y) -5x-5y`
`=x(x+y) -(5x+5y)`
`=x(x+y)-5(x+y)`
`=(x+y)(x-5)`
`6,x(x-y)+2x-2y`
`=x(x-y)+2(x-y)`
`=(x-y)(x+2`
Bạn tách ra từng bài đi ạ. Làm all trong 1 câu nhiều lắm.
Em ko muốn bài giải vậy Thầy xóa đây. Em tự xem lại cách học của mình nhé!
Bài 3:
1. $x^2-9=x^2-3^2=(x-3)(x+3)$
2. $49-x^2=7^2-x^2=(7-x)(7+x)$
3. $4y^4-1=(2y^2)^2-1^2=(2y^2-1)(2y^2+1)=(\sqrt{2}y-1)(\sqrt{2}y+1)(2y^2+1)$
4. $4x^2-25=(2x)^2-5^2=(2x-5)(2x+5)$
5.$x^2-16y^2=x^2-(4y)^2=(x-4y)(x+4y)$
6. $9x^2-1=(3x)^2-1=(3x-1)(3x+1)$
7. $9x^2+6xy+y^2=(3x+y)^2$
8. $4x^2-12xy+9y^2=(2x)^2-2.2x.3y+(3y)^2=(2x-3y)^2$
9. $x^2+4y^2+4xy=x^2+2.x.2y+(2y)^2=(x+2y)^2$
Bài 2:
1. $x^3+2x^2+x=x(x^2+2x+1)=x(x+1)^2$
2. $x^4-4x^3+4x^2=x^2(x^2-4x+4)=x^2(x-2)^2$
3. $5x^2y-35xy+60y=5y(x^2-7x+12)=5y[(x^2-3x)-(4x-12)]$
$=5y[x(x-3)-4(x-3)]=5y(x-3)(x-4)$
4. $2x^2+5x^3+x^2y=x^2(2+5x+y)$
5. $2x^2y-3xy^2+4x^2y^2=xy(2x-3y+4xy)$
6. $-3x^2y+6x^2y^2-9xy^2=-3xy(x-2xy+3y)$
Bài 1:
1. $x^2-x=x(x-1)$
2. $x^2-8x=x(x-8)$
3. $x^2+12x=x(x+12)$
4. $x^3-4x=x(x^2-4)=x(x^2-2^2)=x(x-2)(x+2)$
5. $3x^2-x=x(3x-1)$
6. $2xy+y^2=y(2x+y)$
7. $x^2-xy=x(x-y)$
8. $x^3-x^2y=x^2(x-y)$
Bài 1:
9. $6x-2x^2=2x(3-x)$
10. $2x-4x^2=2x(1-2x)$
11. $3x^2-6x=3x(x-2)$
12. $2x^3-3x^2=x^2(2x-3)$
13. $3x^4-24x=3x(x^3-8)=3x(x^3-2^3)=3x(x-2)(x^2+2x+4)$
14. $4x^2-12x=4x(x-3)$
15. $xy^2-25x=x(y^2-25)=x(y^2-5^2)=x(y-5)(y+5)$
16. $7x^2+14xy=7x(x+2y)$
17. $4x^2y-6xy^2=2xy(2x-3y)$
18. $18x^2y-12x^3=6x^2(3y-2x)$
19. $8xy^2-2x^2y=2xy(4y-x)$
20. $3xy^2+6xyz=3xy(y+2z)$
