Rút gọn biểu thức :
a, x(2×2 – 3) – x2(5x + 1) + x2
b, 3x(x – 2) – 5x(1 – x) – 8(x2 – 3)
c, 1/2 x2(6x – 3) – x( x2 + 1/2 (x + 4)
( Làm đầy đủ các bước ra nhé )
Rút gọn biểu thức : a, x(2×2 – 3) – x2(5x + 1) + x2 b, 3x(x – 2) – 5x(1 – x) – 8(x2 – 3) c, 1/2 x2(6x – 3) – x( x2 + 1/2 (x + 4) ( Làm đầy đủ các bước
By Amara
$a,\ x(2x^2 – 3) – x^2(5x + 1) + x^2$
$=2x^3-3x-5x^3-x^2+x^2$
$=(2x^3-5x^3)+(-x^2+x^2)-3x$
$=-3x^3-3x$
$b,\ 3x(x – 2) – 5x(1 – x) – 8(x^2 – 3)$
$=3x^2-6x-5x+5x^2-8x^2+24$
$=(3x^2+5x^2-8x^2)+(-6x-5x)+24$
$=-11x+24$
`c, 1/2 x^2(6x – 3) – x( x^2 + 1/2) (x + 4)`
`=x^2(3x-3/2)-(x^3+1/2x)(x+4)`
`=3x^3-3/2x^2-x^4-4x^3-1/2x^2-2x`
`=-x^4+(3x^3-4x^3)+(-3/2x^2-1/2x^2)-2x`
`=-x^4-x^3-2x^2-2x`.
Đáp án:
Giải thích các bước giải:
a, x(2x^2 – 3) – x^2(5x + 1) + x^2
=2x^3-3x-5x^3-x^2+x^2
=-3x^3-3x
b, 3x(x – 2) – 5x(1 – x) – 8(x^2 – 3)
=3x^2-6x-5x+5x^2-8x^2+24
=-11x+24
c, 1/2 x^2(6x – 3) – x( x^2 + 1/2 (x + 4)
=3x^3-3/2x^2 – x(x^2+1/2 .x + 2)
=3x^3-3/2x^2 – x^3-1/2.x^2-2x
=2x^3-1/2x^2 – 2x