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13 tháng 11 2021
Bài 1:
\(a,6x^2-15x^3y\\ b,=-\dfrac{2}{3}x^2y^3+\dfrac{2}{3}x^4y-\dfrac{8}{3}xy\)
Bài 2:
\(a,=20x^3-10x^2+5x-20x^3+10x^2+4x=9x\\ b,=3x^2-6x-5x+5x^2-8x^2+24=24-11x\\ c,=x^5+x^3-2x^3-2x=x^5-x^3-2x\)
25 tháng 8 2021
a: Ta có: \(x^2-4x\left(3x-4\right)+7x-5\)
\(=x^2-12x^2+16x+7x-5\)
\(=-11x^2+23x-5\)
b: Ta có: \(7x\left(x^2-5\right)-3x^2y\left(xy-6y^2\right)\)
\(=7x^3-35x-3x^3y^2+18x^2y^3\)
c: Ta có: \(\left(5x+4\right)\left(2x-7\right)\)
\(=10x^2-35x+8x-28\)
\(=10x^2-27x-28\)
BD
1
H9
HT.Phong (9A5)
CTVHS
21 tháng 6 2023
a) \(3x\left(x-3\right)-5x\left(x+7\right)\)
\(=3x^2-9x-5x^2-35x\)
\(=-2x^2-44x\)
b) \(\dfrac{1}{5}x\left(10x-15\right)-2x\left(x-5\right)-12\)
\(=2x^2-3x-2x^2+10x-12\)
\(=7x-12\)
22 tháng 10 2023
1:
a: \(\left(2x-5\right)^2-4x\left(x+3\right)\)
\(=4x^2-20x+25-4x^2-12x\)
=-32x+25
b: \(\left(x-2\right)^3-6\left(x+4\right)\left(x-4\right)-\left(x-2\right)\left(x^2+2x+4\right)\)
\(=x^3-6x^2+12x-8-\left(x^3-8\right)-6\left(x^2-16\right)\)
\(=-6x^2+12x-6x^2+96=-12x^2+12x+96\)
c: \(\left(x-1\right)^2-2\left(x-1\right)\left(x+2\right)+\left(x+2\right)^2+5\left(2x-3\right)\)
\(=\left(x-1-x-2\right)^2+5\left(2x-3\right)\)
\(=\left(-3\right)^2+5\left(2x-3\right)\)
\(=9+10x-15=10x-6\)
2:
a: \(\left(2-3x\right)^2-5x\left(x-4\right)+4\left(x-1\right)\)
\(=9x^2-12x+4-5x^2+20x+4x-4\)
\(=4x^2+12x\)
b: \(\left(3-x\right)\left(x^2+3x+9\right)+\left(x-3\right)^3\)
\(=27-x^3+x^3-9x^2+27x-27\)
\(=-9x^2+27x\)
c: \(\left(x-4\right)^2\left(x+4\right)-\left(x-4\right)\left(x+4\right)^2+3\left(x^2-16\right)\)
\(=\left(x-4\right)\left(x+4\right)\left(x-4-x-4\right)+3\left(x^2-16\right)\)
\(=\left(x^2-16\right)\left(-8\right)+3\left(x^2-16\right)\)
\(=-5\left(x^2-16\right)=-5x^2+80\)
24 tháng 8 2019
\(a,-5x\left(x-3\right)\left(2x+4\right)-\left(x+3\right)\left(x-3\right)+\left(5x-2\right)\left(3x+4\right)\)
\(=-5x\left(2x^2-x-12\right)-\left(x^2-9\right)+15x^2+20x-6x-8\)
\(=-10x^3+5x^2+60x-x^2+9+15x^2+20x-6x-8\)
\(=-10x^3+19x^2+74x+1\)
\(b,\left(4x-1\right)x\left(3x+1\right)-5x^2.x\left(x-3\right)-\left(x-4\right)x\left(x-5\right)\)\(-7\left(x^3-2x^2+x-1\right)\)
\(=\left(4x^2-x\right)\left(3x+1\right)-5x^4-15x^3-\left(x^2-4x\right)\left(x-5\right)\)\(-7x^3+14x^2-7x+7\)
\(=12x^3+x^2-x-5x^4-15x^3-x^3+9x^2+20x\)\(-7x^3+14x^2-7x+7\)
\(=-5x^4-11x^3+24x^2+12x+7\)
\(c,\left(5x-7\right)\left(x-9\right)-\left(3-x\right)\left(2-5x\right)-2x\left(x-4\right)\)
\(=5x^2-52x+63-6+17x-5x^2-2x^2+8x\)
\(=-2x^2-27x+57\)
24 tháng 8 2019
\(d,\left(5x-4\right)\left(x+5\right)-\left(x+1\right)\left(x^2-6\right)-5x+19\)
\(=5x^2+21x-20-x^3-x^2+6x+6-5x+19\)
\(=-x^3+4x^2+22x+5\)
\(e,\left(9x^2-5\right)\left(x-3\right)-3x^2\left(3x+9\right)-\left(x-5\right)\left(x+4\right)-9x^3\)
\(=9x^3-27x^2-5x+15-9x^3-27x^2-x^2+x+20-9x^3\)
\(=-9x^3-55x^2+4x+35\)
\(g,\left(x-1\right)^2-\left(x+2\right)^2\)
\(=x^2-2x+1-x^2-4x-4\)
\(=-6x-3\)
SS
1
Y
26 tháng 5 2023
\(a,3x\left(x-2\right)-5x\left(1-x\right)-8\left(x^2-3\right)\)
\(=3x^2-6x-5x+5x^2-8x^2+24\)
\(=\left(3x^2+5x^2-8x^2\right)+\left(-6x-5x\right)+24\)
\(=0-11x+24\)
\(=-11x+24\)
\(b,\left(7x-3\right)\left(2x+1\right)-\left(5x-2\right)\left(x+4\right)-9x^2+17x\)
\(=14x^2+7x-6x-3-5x^2-20x+2x+8-9x^2+17x\)
\(=\left(14x^2-5x^2-9x^2\right)+\left(7x-6x-20x+2x+17x\right)+\left(-3+8\right)\)
\(=0+0+5\)
\(=5\)
MP
26 tháng 7 2023
\(4.\left(3x+y\right)^2+\left(x+y\right)^2\)
\(=3x^2+6xy+y^2+x^2-2xy+y^2\)
\(=9x^2+6xy+y^2+x^2-2xy+y^2\)
\(=10x^2-4xy+2y^2\)
\(7.\left(x-4\right)^2+\left(x+4y\right)\)
\(=x^2-8x+16+x+4y\)
\(=x^2-7x+16+4y\)
\(10.\left(2x+7\right)^2+\left(-2x-3\right)^2\)
\(=4x^2+28x+49+4x^2+12x+9\)
\(=8x^2+40x+58\)
\(12.-\left(x+1\right)^2-\left(x-1\right)^2\)
\(=-\left(x^2+2x+1\right)-\left(x^2-2x+1\right)\)
\(=-x^2-2x-1+x^2+2x-1\)
\(=4x\)
\(5.-\left(x+5\right)^2-\left(x-3\right)^2\)
\(=-\left(x^2+10x+25\right)-\left(x^2-6x+9\right)\)
\(=-x^2-10-25+x^2+6x-9\)
\(=-16x-16\)
\(8.-\left(-2x+3\right)^2-\left(5x-3\right)^2\)
\(=4x^2+12x+9-25x^2+30x-9\)
\(=-21x^2+42x\)
\(11.-\left(2x-y\right)^2-\left(x+3y\right)^2\)
\(=-4x^2+4xy-y^2-\left(x^2+6xy+9y^2\right)\)
\(=-4x^2+4xy-y^2-x^2-6xy-9y^2\)
\(=-5x^2-2xy-10y^2\)
26 tháng 7 2023
4: =9x^2+6xy+y^2+x^2-2xy+y^2
=10x^2+4xy+2y^2
5: =-x^2-10x-25-x^2+6x-9
=-4x-34
7; \(=x^2-8xy+16y^2+x+4y\)
10: \(=4x^2+28x+49+4x^2+12x+9\)
=8x^2+40x+58
11: =-4x^2+4xy-y^2-x^2-6xy-9y^2
=-5x^2-2xy-10y^2
-(5x - 3)(2x + 4) - (x + 7)(x - 3) + (5x - 2)(3x + 4)
= -(10x2 + 20x - 6x - 12) - (x2 - 3x + 7x - 21) + (15x2 + 20x - 6x - 8)
= -10x2 - 20x + 6x + 12 - x2 + 3x - 7x + 21 + 15x2 + 20x - 6x - 8
= 4x2 - 4x + 25