Question

Tìm x:

a, x\(^2\) - ( x + 2 )\(^2\) = 3

b, - 4x ( x -1 ) + ( 2x + 1 )\(^2\)

c, ( x + \(\dfrac{1}{2}\) )\(^2\) - x\(^2\) + 3 = 0

d, ( x - 2 )\(^2\) = x\(^2\) - 3x

Answer 1

\(a,x^2-\left(x+2\right)^2=3\)

\(\Leftrightarrow x^2-x^2-4x-4=3\)

\(\Leftrightarrow-4x=7\Rightarrow x=-\dfrac{7}{4}\)

\(b,-4x\left(x-1\right)+\left(2x+1\right)^2\)

Để bài thiếu vế phải

\(c,\left(x+\dfrac{1}{2}\right)^2-x^2+3=0\)

\(\Leftrightarrow x^2+x+\dfrac{1}{4}-x^2+3=0\)

\(\Leftrightarrow x=-\dfrac{13}{4}\)

\(d,\left(x-2\right)^2=x^2-3x\)

\(\Leftrightarrow x^2-4x+4-x^2+3x=0\)

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

Answer 2

bn phá hằng đẳng thức ra là xong