Not really sure why you've been downvoted, but anyway...
25 points is the maximum standard load in Summer Semester, so you are fine. It should just be a matter of enrolling into Business Finance and Linear Algebra on your own into 2017 Summer Semester on your study plan (once re-enrolment opens for 2017), and you shouldn't have to submit enrolment variation requests. However, from what I read of the General Chat thread, be prepared to do so just in case. Also, you'll need to hope that your classes don't clash when the university timetable comes out (some time in the middle of Semester 2).
I think it's achievable. From what I know, Linear Algebra is condensed into 6 weeks of teaching, while Business Finance is condensed into 4 weeks with a week's break after 2 weeks. If you do both, you should effectively have (just above) a normal semester's weekly workload throughout the whole Summer Semester. The learning style is slightly different for intensive subjects; you'd want to be comfortable with learning concepts quickly.
If Business Finance is still taught by Rob Brown in Summer Semester, it'll be absolutely fabulous. Not familiar with who takes Linear Algebra in Summer Semester.