(FUVEST)- As funções f e g são dadas por:
f(x)=3/5 x-1
g(x)=4/3 x+a
Sabe-se que f(0) - g(0)=1/3. O valor de f(3)-3.g(1/5) é:
a)0
b)1
c) 2
d)3
e)4
R: alternativa E
f(0) - g(0)=1/3.
3/5*0-1-(4/3*0+a)=1/3
-1-a=1/3
a=-1-1/3
a=-4/3
f(3)-3.g(1/5)
3/5*3-1-3(4/3*1/5-4/3)=
=9/5-1-3(4/15-4/3)=
=9/5-1-12/15+4=
=9/5-12/15+3=
=(27-12+45)/15
=60/15=4
Comments
f(x)=3/5 x-1
g(x)=4/3 x+a
f(0) - g(0)=1/3.
3/5*0-1-(4/3*0+a)=1/3
-1-a=1/3
a=-1-1/3
a=-4/3
f(3)-3.g(1/5)
3/5*3-1-3(4/3*1/5-4/3)=
=9/5-1-3(4/15-4/3)=
=9/5-1-12/15+4=
=9/5-12/15+3=
=(27-12+45)/15
=60/15=4