(5-X)X(7-X)=35 和(5+X)X(7+X)=35

问题描述:

(5-X)X(7-X)=35 和(5+X)X(7+X)=35

①35-12X+X^2=35
X^2-12X=0
X(X-12)=0
X=0,12
②35+12X+X^2=35
X^2+12X =0
X(X+12)=0
X=0,-12