Question

Rút gọn các biểu thức sau :

a) x(2x² - 3) - x²(5x + 1) + x²

b) 3x(x - 2) - 5x(1 - x) - 8(x² - 3)

c) 1/2x²(6x - 3) - x[x² + 1/2] + 1/2(x + 4)

Answer 1

thôi em xin chịu huhuhu !!!

Answer 2

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

Answer 3

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+24ư

cQ= x(x-y) + y(x-y) =(x-y)(x+y)=x^2 - y^2
Thay x=1,5 và y=10 vào pt trên ta được 
1,5^2 -10^2=-97,75

Answer 4

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) 1/2x²(6x - 3) - x[x² + 1/2] + 1/2(x + 4)

=3x3-2/3.2-x3-1/2x+1/2x+1/2x+2

=2.3-3/2x2+2

chúc bn hc tốt

 

Answer 5

a) \(x\left(2x^2-3\right)-x^2\left(5x+1\right)+x^2\)

\(=x.2x^2-x.3-x^2.5x+x^2.1+x^2\)

\(=2x^3-3x-5x^3+x^2-x^2\)

\(=-3x^3-3x\)

b) \(3x\left(x-2\right)-5x\left(1-x\right)-8\left(x^2-3\right)\)

\(=3x.x-3x.2-5x.1-5x.x-8.x^2-8.3\)

\(=3x^2-6x-5x-5x^2-8x^2-24\)

\(=-10x^3-11x-24\)

c) \(\frac{1}{2}x^2\left(6x-3\right)-x\left(x^2+\frac{1}{2}\right)+\frac{1}{2}\left(x+4\right)\)

\(=\frac{1}{2}x^2.6x-\frac{1}{2}x^2.3-x.x^2+x.\frac{1}{2}+\frac{1}{2}.x+\frac{1}{2}.4\)

\(=3x^3-\frac{3}{2}x^2-x^3+\frac{1}{2}x+\frac{1}{2}x+2\)

\(=2x^3-\frac{3}{2}x^2+x+2\)

Answer 6

Câu 1
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

Answer 7

a.x ( 2x^2 - 3) - x^2(5x + 1) + x^2
=x.2x^2 - 3x - x^2.5x - x^2 + x^2
=2x^3 - 3x - 5x^3
=-3x^3 - 3x