先化简,再求值:2(3x-5)+(x-3)^2,其中x=根号2+1
问题描述:
先化简,再求值:2(3x-5)+(x-3)^2,其中x=根号2+1
答
2(3x-5)+(x-3)^2
=6x-10+x^2-6x+9
=x^2-1
=(√2+1)^2-1
=2+2√2+1-1
=2+2√2