a) (3x + 4)2 - (3x - 1).(3x + 1) = 49
=> (3x + 4).3x + (3x + 4).4 - (9x2 - 1) = 49
=> 9x2 + 12x + 12x + 16 - 9x2 + 1 = 49
=> 24x + 17 = 49
=> 24x = 49 - 17
=> 24x = 32
=> \(x=\frac{32}{24}=\frac{4}{3}\)
Vậy \(x=\frac{4}{3}\)
b) (2x + 1)2 - (x - 1)2 = 0
=> (2x + 1 - x + 1).(2x + 1 + x - 1) = 0
=> (x + 2).3x = 0
=> (x + 2).x = 0
\(\Rightarrow\left[\begin{array}{nghiempt}x+2=0\\x=0\end{array}\right.\) \(\Rightarrow\left[\begin{array}{nghiempt}x=-2\\x=0\end{array}\right.\)
Vậy \(\left[\begin{array}{nghiempt}x=-2\\x=0\end{array}\right.\)
a)
➜9x2+24x+16-9x2+1=49
➜24x +17=49
⇒24x=49
⇒x=4/3
b)⇒4x2+4x+1-x2+2x-1=0
⇒3x2+6x=0
⇒3x(x+3)=0
⇒3x=0 hoặc x+3 =0
⇒x=0 hoặc x=-3
