Bring (1, 0) into the equation and get b =-1-a.

When b=- 1-a is brought into the equation, ax 2-(1+a) x+1= 0 is obtained.

According to the equation discriminant > 0, we can judge a ≠1;

Third question

The constant is 2.

The factor ax 2-( 1+a) x+ 1 = 0 is decomposed into (ax- 1)(x- 1)=0, and the solution is b (1a, 0).

Because 0

AB= 1/a- 1

CD= 1/a+ 1

ABCD is an isosceles trapezoid, and the area of triangle APC = the area of triangle DPB.

∴△CDA minus△△ DAB = s1-S2 = CD-AB = 2.