Vì \(x^2-y^2-z^2=0\Rightarrow x^2-y^2=z^2\)
Biến đổi vế trái ta có :
\(\left(5x-3y+4z\right)\left(5x-3y-4z\right)=\left(5x-3y\right)^2-16z^2\)
\(=25x^2-30xy+9y^2-16\left(x^2-y^2\right)\)
\(=25x^2-30xy+9y^2-16x^2+16y^2\)
\(=9x^2-30xy+25y^2\)
\(=\left(3x-5y\right)^2\) ( ĐPCM)
cho x^2-y^2-z^2=0 chứng minh rằng: (5x-3y+4z)*(5x-3y-4z)=(3x-5y)^2
Cho \(^{x^2-y^2-z^2=0.CMR:\left(5X-3Y+4Z\right)\left(5Z-3Y-4Z\right)=\left(3X-5Y\right)^2}\)
Nếu x2=y2+z2. chứng minh rằng (5x-3y+4z)(5x-3y-4z)=(3x-5y)2
chứng minh rằng : (5x-3y+4z)(5x- 3y-4z)=(3x-5y)2 nếu x2=y2+z2
Cho x2-y2-z2=0
C/m (5x-3y+4z).(5x-3y-4z)=(3x-5y)2
cho x2-y2-z2=0
chúng minh : (5x-3y+4z)(5x-3y-4z)=(3x-5y)2
Cho x^2 -y ^2=4z^2 . CMR: (5x-3y+8z)(5x-3y-8z)=(3x-5y)^2
cho x2 - y2 -z2 = 0
c/m ( 5x -3y + 4z) nhân ( 5x - 3y - 4z ) = ( 3x - 5y)2
a) cho x^2 = y^2+z^2. chứng minh: (5x-3y+4z)(5x-3y-4z)=(3x-5y)^2
b) cho 10x^2=10y^2+z^2. chứng minh: (7x-3y+2z)(7x-3y-2z)=(3x-7y)^2