Question

Giúp mình 4 câu này với :<

Bài 1: Tìm x

a) 2x(x - 3) + x - 3 = 0

b) x² (x - 6) - x² + 36 = 0

c) 5 - 6x + x² = 0

d) x(x + 5) + x(x + 15) = 0

Cảm ơn các bạn nhaaaa

Answer 1

a: Ta có: \(2x\left(x-3\right)+x-3=0\)

\(\Leftrightarrow\left(x-3\right)\left(2x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{1}{2}\end{matrix}\right.\)

b: Ta có: \(x^2\left(x-6\right)-x^2+36=0\)

\(\Leftrightarrow\left(x-6\right)\left(x^2-x-6\right)=0\)

\(\Leftrightarrow\left(x-6\right)\left(x-3\right)\left(x+2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=3\\x=-2\end{matrix}\right.\)