[請益] 一到數學題
1.若 x^2-7x+2=0 則 x+1/x 的值是多少??
我ㄧ開始想法是 x^2+2=7x 同除x後 ->> x+2/x=7 來代入所求
但怎麼代都有未知數@@"
不好意思~~~在一題
2. m為實數,y=x^2+(m-1)x+(m+7) 若y=0,有一根為1+根號3,則下列何者為真?
A.m<-5 B.m<-4 C.m<-3 D.m>-2
這一題 我逆算回去對照原方程式發現 x項求得m=-1 常數項的m=-9....答案變AD= =
不知道怎解這題~~~謝謝各位了
以上兩題我都沒有解答(弄丟了)~~~~
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