Question

URGENT !!!! Cum sa rezolv ??????

Answer 1

f(x)=(m+1)x-3
g(x)=5x-n
(f°g)(x)=f(g(x))=f(5x-n)=(m+1)(5x-n)-3=5mx-mn+5x-n-3=x(5m+5)-mn-n-3
(f°g)(x)=x 
Deci rezulta ca:
x(5m+5)-mn-n-3=x
Si egalam coeficientii si formam sistemul:
$\left \{ {{5m+5=1} \atop {-mn-n=3}} \right.$
Din 5m+5=1 => 5m=-4 => m=-4/5.
Si introducem valoarea lui m in a doua ecuatie:
-(-4/5)n-n=3
4n/5-n=3
(4n-5n)/5=3
-n/5=3
-n=15
n=-15