Thực hiện các phép tính sau :
a.
b.
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\(a,=x+x^2-x^3+x^4-x^5+1+x-x^2+x^3-x^4-x-x^2+x^3-x^4+x^5+1+x-x^2+x^3-x^4\\ =2x-2x^2+2x^3-2x^4\)
Bài 3:
a: Ta có: \(\left(y-5\right)\left(y+8\right)-\left(y+4\right)\left(y-1\right)\)
\(=y^2+8y-5y-40-y^2+y-4y+4\)
=-36
b: Ta có: \(y^4-\left(y^2-1\right)\left(y^2+1\right)\)
\(=y^4-y^4+1\)
=1
Bài 2:
a: \(\left(2a-b\right)\left(4a+b\right)+2a\left(b-3a\right)\)
\(=8a^2+2ab-4ab-b^2+2ab-6a^2\)
\(=2a^2-b^2\)
b: \(\left(3a-2b\right)\left(2a-3b\right)-6a\left(a-b\right)\)
\(=6a^2-9ab-4ab+6b^2-6a^2+6ab\)
\(=6b^2-7ab\)
c: \(5b\left(2x-b\right)-\left(8b-x\right)\left(2x-b\right)\)
\(=10bx-5b^2-16bx+8b^2+2x^2-xb\)
\(=3b^2-7xb+2x^2\)
a) (2x+12x−1−2x−12x+1):4x10x−5=(2x+1)2−(2x−1)2(2x−1)(2x+1).10x+54x(2x+12x−1−2x−12x+1):4x10x−5=(2x+1)2−(2x−1)2(2x−1)(2x+1).10x+54x
=4x2+4x+1−4x2+4x−1(2x−1)(2x+1).5(2x+1)4x4x2+4x+1−4x2+4x−1(2x−1)(2x+1).5(2x+1)4x
=8x.5(2x+1)(2x−1)(2x+1).4x=102x−18x.5(2x+1)(2x−1)(2x+1).4x=102x−1
b) (1x2+x−2−xx+1):(1x+x−2)(1x2+x−2−xx+1):(1x+x−2)
=(1x(x+1)+x−2x+1):1+x2−2xx(1x(x+1)+x−2x+1):1+x2−2xx
=1+x(x−2)x(x+1).xx2−2x+11+x(x−2)x(x+1).xx2−2x+1
=(x2−2x+1)xx(x+1)(x2−2x+1)=1x+1(x2−2x+1)xx(x+1)(x2−2x+1)=1x+1
c) 1x−1−x3−xx2+1.(1x2−2x+1+11−x2)1x−1−x3−xx2+1.(1x2−2x+1+11−x2)
=1x−1−x3−xx2+1.[1(x−1)2−1(x−1)(x+1)]
a) (2x+12x−1−2x−12x+1):4x10x−5(2x+12x−1−2x−12x+1):4x10x−5
= 0 - 0
= 0
b) (1x2+x−2−xx+1):(1x+x−2);(1x2+x−2−xx+1):(1x+x−2)
= (x-xx+1) : (2x-2) : (x-xx+1) : (2x-2)
c) 1x−1−x3−xx2+1.(1x2−2x+1+11−x2)
= -2x-1-xx2+1. (14 - 4x)
= -x2-1-xx2+14-4x
= -6x-xx2+13
a. (x + 1)(1 + x - 2x + 3x - 4x) - (x - 1)(1 + x + 2x + 3x + 4x)
= (x + 1)(1 - 2x) - (x - 1)( 1 + 10x)
= x - 2x2 + 1 - 2x - x - 10x2 + 1 + 10x
= x - 2x - x + 10x - 2x2 - 10x2 + 1 + 1
= 8x - 8x2 + 2
= -8x + 8x + 2
= -(-8x + 8x + 2)
= 8x2 - 8x - 2
= 8x2 - 4x - 4x - 2
= 4x(2x - 1) - 2(2x + 1)