无论x y取何实数,整式x²-8x+y²-10y+42的值总是( )
问题描述:
无论x y取何实数,整式x²-8x+y²-10y+42的值总是( )
答
x²-8x+y²-10y+42=(x²-8x+16)+(y²-10y+25)+1=(x-4)²+(y-5)²+1≥1
无论x y取何实数,整式x²-8x+y²-10y+42的值总是( )
x²-8x+y²-10y+42=(x²-8x+16)+(y²-10y+25)+1=(x-4)²+(y-5)²+1≥1