Toán Lớp 8: a) 2x(x+5) b) x(4x+1) c) x^2(1-y) d) 2xy(y^2+1) e) (4x^2+4x-3) : (2x+3) g) x^3-3x^2+2) : (x+1)

Question

Toán Lớp 8:  a) 2x(x+5) b) x(4x+1)  c) x^2(1-y) d) 2xy(y^2+1) e) (4x^2+4x-3) : (2x+3) g) x^3-3x^2+2) : (x+1)

tuanh · Answer

Giải đáp:

$a) 2x.(x+5)$

$= 2x.x+2x.5$

$= 2x²+10x$

$b) x.(4x+1)$

$= x.4x+x.1$

$= 4x²+x$

$c) x².(1-y)$

$= x².1-x².y$

$= x²-x²y$

$d) 2xy.(y²+1)$

$= 2xy.y²+2xy.1$

$= 2xy³+2xy$

$e) (4x²+4x-3):(2x+3)$

$= (4x²+6x-2x-3):(2x+3)$

$= [2x.(2x+3)-1.(2x+3)]:(2x+3)$

$= (2x-1).(2x+3):(2x+3)$

$= 2x-1$

$g) (x³-3x²+2):(x-1)$

$= (x³-x-2x+2):(x-1)$

$= [x.(x²-1)-2.(x-1)]:(x-1)$

$= [x.(x-1).(x+1)-2.(x-1)]:(x-1)$

$= (x-1).(x²-2x-2):(x-1)$

$= x^2-2x-2$

maianhtuanh · Answer

Giải đáp+Lời giải và giải thích chi tiết:

a)2x(x+5)

=2x^2 +10x

b)x(4x+1)

=4x^2 +x

c)x^2 (1-y)

=x^2 -x^2 y

d)2xy(y^2 +1)

=2xy^3 +2xy

e)(4x^2 +4x-3):(2x+3)

=(4x^2 +6x -2x-3)/(2x+3)

=(2x(2x+3)-(2x+3))/(2x+3)

=((2x+3)(2x-1))/(2x+3)

=2x-1

Sửa đề :g)(x^3 -3x^2 +2):(x-1)

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

=(x(x^2 -2x-2)-(x^2 -2x-2))/(x-1)

=((x^2 -2x-2)(x-1))/(x-1)

=x^2 -2x-2