Her new balance is 886.07 dollars hope this helps
Answer : 
Given expression is 
To make perfect square trinominal we use completing the square method
In completing the square method we add and subtract the half of square of coefficient of middle term
Here coefficient of middle term is -7
Half of -7 is 
Square of
is
=
So the expression becomes
that gives perfect square trinomial
Hence , the value of 'c' is
For the 1st one we need to solve x. x-y=2 step1: x-y+y=2+y answer: x=y+2