Question

1.Tìm x:
a,x mũ 3 - 16 = 0
b,x mũ 4 - 2x mũ 3 + 10x mũ 2 - 20x = 0
c,(2x - 3)mũ 2 = (x + 5)mũ 2
d,x mũ 2(x - 1) - 4x mũ 2 + 8x -4 = 0
e,x mũ 3 - 11x mũ 2 + 30x = 0
P/s:Giúp mk vs chiều mai mk phải nộp rồi

Answer 1

b: \(\Leftrightarrow x\left(x^3-2x^2+10x-20\right)=0\)

\(\Leftrightarrow x\left(x-2\right)=0\)

hay \(x\in\left\{0;2\right\}\)

c: \(\Leftrightarrow\left(2x-3-x-5\right)\left(2x-3+x+5\right)=0\)

=>(x-8)(3x+2)=0

hay \(x\in\left\{8;-\dfrac{2}{3}\right\}\)

d: \(\Leftrightarrow x^2\left(x-1\right)-4\left(x-1\right)^2=0\)

\(\Leftrightarrow\left(x-1\right)\left(x^2-4x+4\right)=0\)

\(\Leftrightarrow\left(x-1\right)\left(x-2\right)^2=0\)

=>x=1 hoặc x=2