Question

giúp mik ạ

Answer 1

`11,`

`a,`

`-7x(6+2x)`

`= -7x*6-7x*2x`

`= -42x-14x^2`

`b,`

`5x(3x^2-4x+5)`

`= 5x*3x^2+5x*(-4x)+5x*5`

`= 15x^3-20x^2+25x`

`c,`

`3x^2(x^2+2x-1)`

`= 3x^2*x^2+3x^2*2x+3x^2*(-1)`

`= 3x^4+6x^3-3x^2`

Answer 2

`d,`

`(2y^3-y^2+y-4)y^2`

`= y^2*2y^3+y^2*(-y^2)+y^2*y+y^2*(-4)`

`= 2y^5-y^4+y^3-4y^2`

`e,`

`-2y^3(-y^3-y+5y-1)`

`= -2y^3*(-y^3)-2y^3*(-y)-2y^3*5y-2y^3*(-1)`

`= 2y^6+2y^4-10y^4+2y^3`

`g,`

`(t-1)(t+2)`

`= t(t+2)-1(t+2)`

`= t^2+2t-t-2`

`= t^2+t-2`

Answer 3

`h,`

`-2/3x^2(-5/4x^2-6x+3/8)`

`= -2/3x^2*(-5/4x^2)-2/3x^2*(-6x)-2/3x^2*3/8`

`= 5/6x^4+4x^3-1/4x^2`

`i,`

`(-0,4x-1/5x^2)(-5/2x^4-10x^3+6)`

`= -0,4x(-5/2x^4-10x^3+6)-1/5x^2(-5/2x^4-10x^3+6)`

`= x^5+4x^4-2,4x+1/2x^6+2x^5-1,2x^2`

`= 1/2x^6+3x^5+4x^4-1,2x^2`

`k,`

`1/2x(4x^3-4/3x)`

`= 1/2x*4x^3+1/2x*(-4/3x)`

`= 2x^4-2/3x^2`

Answer 4

`l,`

`(x-1)(2x^2-3x+1)`

`= x(2x^2-3x+1)-1(2x^2-3x+1)`

`= 2x^3-3x^2+x-2x^2+3x-1`

`= 2x^3-5x^2+4x-1`

`m,`

`(2+x)(-x^2+3x-1)`

`= 2(-x^2+3x-1)+x(-x^2+3x-1)`

`= -2x^2+6x-2-x^3+3x^2-x`

`= x^2+5x-2`

`n,`

`(3x^2-4)(x+3)`

`= 3x^2(x+3)-4(x+3)`

`= 3x^3+9x^2-4x-12`

Answer 5

Cậu chia ra được k ạ :<. Chứ như hồi sáng mk làm hơi lâu:<.