For question 1

Here is the concept.

if equation is satisfied by more than 2 values of x then a = b = c =0.

Reduce your equation in standard quadratic form and then equate all coefficients to zero and solve for p, q, r

2) length is x + 10

perimeter 2 ( x + x + 10) = 4x + 20

perimeter is greate than 64.

so 4x + 20 >64

x > 22

3) remaining questions ar not clear.

but still let me tell you that (x-13)(x+23) < 0 is true for -23 < x < 13