Question

tìm x biết 

a, 2(5x-8) -3 (4x-5) = 4(3x-4) + 11

b, \(2x(6x-2x^3) + 3x^2(x-4) =8\)

c,\(2(x^3-1)-2x^2(x+2x^4)+(4x^3+4)\)

d,\((2x)^2 (4x-2) - (x^3-8x^2)=15\)

Answer 1

a. \(2.\left(5x-8\right)-3.\left(4x-5\right)=4.\left(3x-4\right)+11\Leftrightarrow10x-16-12x+15=12x-16+11\\ \)

\(\Leftrightarrow-2x-1=12x-5\Leftrightarrow14x-4=0\Leftrightarrow x=\frac{2}{7}\)

Answer 2

\(a,2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)

\(\Leftrightarrow10x-16-12x+15=12x-16+11\)

\(\Leftrightarrow10x-12x-12x=-16+11+16-15\)

\(\Leftrightarrow-14x=-4\)

\(\Leftrightarrow x=\frac{-4}{-14}=\frac{2}{7}\)