先化简,再求值.我需要你!(1)(a-1)²-a(a+1),其中a=(根号2)-1(2)(a-2)(a-3)+2(a+6)(a-5)-3(a²-7a+13),其中a=-(7/18)
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![先化简,再求值.我需要你!(1)(a-1)²-a(a+1),其中a=(根号2)-1(2)(a-2)(a-3)+2(a+6)(a-5)-3(a²-7a+13),其中a=-(7/18)](/uploads/image/z/311428-28-8.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC.%E6%88%91%E9%9C%80%E8%A6%81%E4%BD%A0%21%EF%BC%881%EF%BC%89%EF%BC%88a-1%EF%BC%89%26%23178%3B-a%EF%BC%88a%2B1%EF%BC%89%2C%E5%85%B6%E4%B8%ADa%3D%EF%BC%88%E6%A0%B9%E5%8F%B72%EF%BC%89-1%EF%BC%882%EF%BC%89%EF%BC%88a-2%EF%BC%89%EF%BC%88a-3%EF%BC%89%2B2%EF%BC%88a%2B6%EF%BC%89%EF%BC%88a-5%EF%BC%89-3%EF%BC%88a%26%23178%3B-7a%2B13%EF%BC%89%2C%E5%85%B6%E4%B8%ADa%EF%BC%9D%EF%BC%8D%287%2F18%29)
先化简,再求值.我需要你!(1)(a-1)²-a(a+1),其中a=(根号2)-1(2)(a-2)(a-3)+2(a+6)(a-5)-3(a²-7a+13),其中a=-(7/18)
先化简,再求值.我需要你!
(1)(a-1)²-a(a+1),其中a=(根号2)-1
(2)(a-2)(a-3)+2(a+6)(a-5)-3(a²-7a+13),其中a=-(7/18)
先化简,再求值.我需要你!(1)(a-1)²-a(a+1),其中a=(根号2)-1(2)(a-2)(a-3)+2(a+6)(a-5)-3(a²-7a+13),其中a=-(7/18)
1、原式=a^2-2a+1-a^2-a
=-3a+1
=-3(√2-1)+1
=-3√2+4
2、原式=a^2-5a+6+2a^2+2a-60-3a^2+21a-39
=(1+2-3)a^2+(-5+2+21a)+(6-60-39)
=18a-93
=18*(-7/18)-93
=-7-93
=-100