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2⁴x-3x=145-225:51(sửa đề)

=> 13x=145-75/17

=> 13x=2390/17

=> x=2390/221

Sao chép bài ai hả?

=> ko có

k) 99-96+93-...+9-6+3 

=(99-96)+(93-90)+...+(9-6)+3

=3+3...+3+3

=3*16+3

=48+3=51

x³+1= (x+1)(x²-x+1)

8+x³=2³+x³=(2+x)(4-2x+x²)

27x³-64y³= (3x)³-(4y)³= (3x-4y)(9x²+12xy+16y²)

\(\dfrac{x^3}{64}\)-\(\dfrac{1}{125}\)(sửa đề)=(x/4)³-(1/5)³

=(x/4-1/5)(x/16+x/20+1/25)

a) (x+3)(x-2)=x²+3x-2x-6 =x²+x-6

b) (x+6)(2x+1)= 2x²+12x+x+6 = 2x²+13x+6

c) (x-5)(2-x) = -x²+2x+5x-10= -x²+7x-10

d) (-x+1)(x-2)= -x²+x+2x-2= -x²+3x-2

e) (-5x-3)(2-x) = 5x²-10x+3x-6= 5x²-7x-6

f) (x+1)(x-2) = x²-2x+x-2= x²-x-2

=y(x-5)+2(x-50)

=y(x-5)+2(x-5)-90

=(x-5)(y+2)-90

a. (2x+3y)²= (2x)²+2.2x.3y+(3y)²

=4x²+12xy+9y²

b. 2(\(\dfrac{1}{2}\)x²+y)(x²-2y)

=(x²+2y)(x²-2y)

=x⁴-4y²

c, (x+y+z)²= [(x+y)+z]²

=(x+y)²+2(x+y)z+z²

=x²+2xy+y²+2xz+2yz+z²

=x²+y²+z²+2xy+2yz+2xz

Cho x + y + z = 0; xyz ≠ 0 . Tính \(A=\dfrac{x^2}{yz}+\dfrac{y^2}{xz}+\dfrac{z^2}{xy}\)