Who do i show my work and how do i do it

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.

According to the general equation for conditional probability, if p(ab) = 4/5 and p(b)= 5/6, what is p(a|b)? a. 8/9 b. 35/36 c. 24/25 d. 15/16

Brainliest find the value of a^n b^n if n=3,a=100,and b=1/4