Question

4a+90a 86b-77b 209m+1 302n-n

Answer 1

4a+90a=(4+90)a=94a
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86b-77b=(86-77)b=9b
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$209m+1$
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$209m+1m=(209+1)m=210m$
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$302n-n=(302-1)n=301n$