XX-2X x 2 +68=100

\(x^2-4x+68=100\)

\(X^2-4X-32=0\)

(X-8) x(X+4)=0

X=8 hoặc x=-4

xx - 2x x 2 = 68

x(x - 4) + 68 = 100

x(x - 4) = 32

X x(x - 4) = 8 x (8 - 4)

Vậy x = 8

XX là gì bn

\(xx-2x\times2+68=100\)

\(\Leftrightarrow x^2-4x=100-68\)

\(\Leftrightarrow x\left(x-4\right)=32\)

\(\Leftrightarrow x\left(x-4\right)=8\times4\)

\(\Leftrightarrow x=8\)

thanks bạn

1) \(2x\left(x-5\right)+\left(x-2\right)\left(x+3\right)=2x^2-10x+x^2+3x-2x-6=3x^2-9x-6\)

2) \(\left(2x-5\right)\left(1-x\right)-\left(x-3\right)\left(-2x\right)=2x-2x^2-5+5x+2x^2-6x=x-5\)

3) \(\left(4x-3\right)\left(4x-3\right)-\left(3x+2\right)\left(3x-2\right)=\left(4x-3\right)^2-9x^2+4=16x^2-24x+9-9x^2+4\)

\(=7x^2-24x+13\)

4) \(\left(2x-1\right)\left(2x+1\right)\left(2x+1\right)-4\left(x^2+1\right)=\left(2x-1\right)[\left(2x+1\right)^2]-4x^2-4\)

\(=\left(2x-1\right)\left(4x^2+4x+4\right)-4x^2-4=8x^3+8x^2+8x-4x^2-4x-4-4x^2-4=8x^3+4x-8\)

5) \(3x\left(2x-8\right)-\left(2-6x\right)\left(5+x\right)=6x^2-24x-10-2x+30x+6x^2=12x^2+4x-10\)

6) \(x\left(3x-18\right)-3\left(x-4\right)\left(x-2\right)+8=3x^2-18x-3x^2+6x+12x-24+8=-16\)

7) \(\left(x+2\right)\left(x^2-2x+4\right)-x^2\left(x-2\right)-2x^2=x^3+8-x^3+2x^2-2x^2=8\)

54 + 68,7 x 99 + 14,7

= 68,7 + 68,7 x 99

= 68,7 x 100

= 6870

54 + 68,7 x 99 + 14,7

= 68,7 + 68,7 x 99

= 68,7 x 100

= 6870

54 + 68,7 x 99 + 14,7

= 68,7 + 68,7 x 99

= 68,7 x 100

= 6870

a) x/-3=y/-7=2x/-6=4y/-28=2x+4y/(-6)+(-28)= 68/-34=-2

Vậy x/-3 = -2 => x=(-2)x(-3)=6

       y/-7= -2 => y=(-2)x(-7)=14

      nhớ chọn nhé

Chọn đáp án C.

Điều kiện  x   ≥   0 ;   x   ≠   1 ;   x   ≠ 4 .