88mL * 5M = 0.44 mol HCl
32mL * 8M = 0.256 mol HNO3
because both HCl and HNO3 are strong acids (aka they dissociate completely into H and Cl and NO3), 0.44 moles of HCl at equilibrium would make 0.44 moles H+; and 0.256 moles HNO3 produces 0.256 moles H+ also. so add these and there are 0.696 moles. divide by the volume, 1L, and it's 0.696 M H+ (first answer).
the OH- concentration is equal to the quantity (10^-14)/[H+]. so (10^-14)/(0.696) = 1.44 x 10^-14 M for the OH- concentration.
the pH is the neg-log of 0.696, which is equal to a pH of 0.157 (which is very low, but that's because it's strong acids and no bases to counter it)
I've been doing jillions of chem problems today to study for my exam.