a) \(\left(x+3\right)^2-\left(2x+1\right).\left(2x-1\right)=22\)
\(\Leftrightarrow x^2+6x+9-\left(4x^2-1\right)=22\)
\(\Leftrightarrow x^2+6x+9-4x^2+1=22\)
\(\Leftrightarrow-3x^2+6x-12=0\)
\(\Leftrightarrow x^2-2x+4=0\)
\(\Leftrightarrow\left(x^2-2x+1\right)+3=0\)
\(\Leftrightarrow\left(x-1\right)^2+3=0\)(vô lý)

b)   \(\left(4x+3\right)\left(4x-3\right)-\left(4x-5\right)^2=46\)
\(\Leftrightarrow16x^2-9-\left(16x^2-40x+25\right)=46\)
\(\Leftrightarrow16x^2-9-16x^2+40x-25-46=0\)
\(\Leftrightarrow40x-80=0\)
\(\Leftrightarrow x=2\)

Bài 1: 

\(\left(2x-5\right)^2-4\left(2x-5\right)+4=0\)

\(\left(2x-5\right)^2-2\left(2x-5\right)\left(2\right)+2^2=0\)

\(\left(2x-5-2\right)^2=0\)

\(2x-5-2=0\)

\(2x-7=0\)

\(2x=0+7\)

\(2x=7\)

\(x=\frac{7}{2}\)

Bài 3: 

\(\left(4x+3\right)\left(4x-3\right)-\left(4x-5\right)^2=46\)

\(\left(4x\right)^2-3^2-16x^2+40x-25=46\)

\(4^2x^2-3^2-16x^2+40x-25=46\)

\(16x^2-9-16x^2+40x-25=46\)

\(-34+40x=46\)

\(40x-34=46\)

\(40x=46+34\)

\(40x=80\)

\(x=2\)

bài 2:

a) \(81^2=\left(80+1\right)^2=80^2+2.80+1=6400+160+1=6561\)

b) \(99^2=\left(100-1\right)^2=100^2-2.100+1=10000-200+1=8801\)

          \(\left(4x+3\right)\left(4x-3\right)-\left(4x-5\right)^2=46\)

\(\Leftrightarrow\)\(16x^2-9-\left(16x^2-40x+25\right)=46\)

\(\Leftrightarrow\)\(40x-34=46\)

\(\Leftrightarrow\)\(40x=80\)

\(\Leftrightarrow\)\(x=2\)

Vậy...

(4x-3).(4x+2) + (4x+5).(1-4x) = 2.5²

16x² + 8x - 12x - 6 + 4x - 16x² + 5 - 20x = 50

(16x² - 16x²) + ( 8x-12x+4x-20x) - (6-5) = 50

-20x = 50

x = -5/2

a) \(\left(5x-2\right)\left(5x+2\right)-\left(5x+3\right)\left(5x-4\right)=0\)

\(\Leftrightarrow5x+8=8\)

\(\Leftrightarrow5x=8-8\)

\(\Leftrightarrow x=5.0\)

\(\Leftrightarrow x=0\)

b) 

câu b sao bạn

ai giupws với