1).
3x-5x=
(3-5)x=
-2x
2) 2x(x-3)-2(x-5)
2(x× (x-3)-(x-5)
2(x^2-3x-x+5)
2(x^2-4x+5)
3).4x^2y^3:(-2xy^3)
4x^2y^3:(-(2xy)^3)
- 4x^2y^3 totu supra (2xy)^3=
4x^2y^3 totu supra 8x^3y^3=
-1 supra 2x
4).(2x+1)(x-3)=
2x^2-6x+x-3=
2x^2-5x-3
5). (2x+1)^2=
(2x)^2 +2×2x × 1 +1^2
4x^2+4x+1
6).(x-3)^2=
x^2-2x×3+3^2=
x^2-6x+9
7).(5x-1)(5x+1)=
(5x)^2-1^2
25x^2-1
8).(x+2)^2-(2x-1)^2+(x+5)(x-5)=
x^2+4x+4-(4x^2-4x+1)+x^2-25=
x^2+4x+4-4x^2+4x-1+x^2-25=
-2x^2+8x-22
Descompuneti:
1).x^2+4x+4=
x^2+2× x × 2 + 2^2=
(x+2)^2
2).x^2-6x+9=
x^2+2×x×3+3^2=
(x+3)^2
3).x^2-25=
x^2-25=
(x-5)×(x+5)
Scuze doar atat am stiut