Question

CẦN GẤP CẦN GẤP :  a) (2x+1)²-(2x-3)²=5

b) (2x-1).(2x+1)-(3x-2)(3x+2)=-2

Answer 1

Answer 2

b) (2x)^2 -1 - (3x)^2 + 4=-2

   -5x^2=1

   x^2=-1/5

x không tồn tại

Answer 3

a) \(\left(2x+1\right)^2-\left(2x-3\right)^2=5\Leftrightarrow\left(2x+1-2x+3\right)\left(2x+1+2x-3\right)=5\Leftrightarrow4\left(4x-2\right)=5\Leftrightarrow16x-8=5\Leftrightarrow16x=13\Leftrightarrow x=\dfrac{13}{16}\)b) \(\left(2x-1\right)\left(2x+1\right)-\left(3x-2\right)\left(3x+2\right)=-2\Leftrightarrow4x^2-1-9x^2+4=-2\Leftrightarrow5x^2=5\Leftrightarrow x^2=1\Leftrightarrow x=\pm1\)