Question 90536
M^2-5MN+3N^2
M^2+4MN-2N^2
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M^4-5M^3N+3M^2N^2+4M^3N-20M^2N^2+12MN^3-2M^2N^2+10MN^3-6N^4
NOW COMBINE LIKE TERMS:
M^4-M^3N-19M^2N^2+22MN^3-6N^4 ANSWER.