计算:(x+1)x=7 (x-1)(x+2)=30 (3-x)(3-x)+x=9

问题描述:

计算:(x+1)x=7 (x-1)(x+2)=30 (3-x)(3-x)+x=9

X^2+X-7=0 X1=根29 -1 X2= - 1- 根29
X^2+X-2=0 X1=-2 X2=1
9-6X+X^2+X=9 X^2-5X=0 X(X-5)=0 X1=0 X2=5