The lines y = 2x - 1 and y = -2x + 3 intersect at exactly one point which means this system has exactly one solution. so the system is consistent and independent
50$ per month for 12 years would mean she spent only (50 x 12) 600$ per year.
She actually spent $711, her forecast was off target by (600-7111) $111.
She exceeded her budget by $111
