(1)(x²-2y²-z²0-(-y²+3x²-z ²)+(5x²-y²+2x²)

问题描述:

(1)(x²-2y²-z²0-(-y²+3x²-z ²)+(5x²-y²+2x²)

(x²-2y²-z²)-(-y²+3x²-z ²)+(5x²-y²+2z²)
=x²-2y²-z²+y²-3x²+z ²+5x²-y²+2z²
=3x²-2y²+2z²

最后一个括号应为 (5x²-y²+2z²)(x²-2y²-z²) -(-y²+3x²-z²) + (5x²-y²+2z²)= x²-2y²-z² + y²-3x²+z² + 5x²-y...