Respuesta :

Step-by-step explanation:

m+n=5 and m-n=3

making m the subject of the formula in (m+n=5)

m=5-n

substitute your answer (m=5-n) in the second equation (m-n=3)

you get (5-n-n=3)

5-2n=3

collect like terms

5-3=2n

2=2n

2n=2

n=2÷2

n=1