Question

a) x2(x - 5) + 5 - x = 0; b) 3x4 - 9x3 = -9x2 + 27x;

c) x2(x + 8) + x2 = -8x; d) (x + 3)(x2 -3x + 5) = x2 + 3x.

e) 3x(x - 1) + x - 1 = 0;

f) (x - 2)(x2 + 2x + 7) + 2(x2 - 4) - 5(x - 2) = 0;

g) (2x - 1)2 - 25 = 0;

h) x3 + 27 + (x + 3)(x - 9) = 0.

i)8x3 - 50x = 0; k) 2(x + 3)-x2 - 3x = 0;

m)6x2 - 15x - (2x - 5)(2x + 5) =

Answer 1

a: \(\Leftrightarrow\left(x-5\right)\left(x+1\right)\left(x-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-1\\x=1\end{matrix}\right.\)

d: \(\Leftrightarrow\left(x+3\right)\left(x^2-4x+5\right)=0\)

\(\Leftrightarrow x+3=0\)

hay x=-3