Il y a 5ans Thomas avait 5 fois l'âge de benoit aujourd'hui Thomas a 3 fois l âge de Benoît quel est l'âge de benoit

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Benoit a 10 ans

Explication étape par étape :

Laisser :

Âge de Thomas = x

Benoit age = y

il y a 5 ans :

x - 5 = 5 (y - 5)

x - 5 = 5y - 25 - - (1)

Aujourd'hui :

x = 3y - - (2)

Mettez x = 3y dans (1)

3 ans - 5 = 5 ans - 25

Recueillir des termes similaires

3 ans - 5 ans = - 25 + 5

-2a = - 20

Diviser les deux côtés par - 2

y = 10

let's add {f(x)=x+1}f(x)=x+1 and {g(x)=2x}g(x)=2x together to make a new function.

f(x)+g(x) =(x+1)+(2x)=x+1+2x=3x+1

let's call this new function hh. so we have:

{h(x)}={f(x)}+{g(x)}{=3x+1}h(x)=f(x)+g(x)=3x+1

we can also evaluate combined functions for particular inputs. let's evaluate function hh above for x=2x=2. below are two ways of doing this.

method 1: substitute x=2x=2 into the combined function hh.

h(x)

h(2)

​    

=3x+1

=3(2)+1

=7

​ since h(x)=f(x)+g(x)h(x)=f(x)+g(x), we can also find h(2)h(2) by finding f(2) +g(2)f(2)+g(2).

first, let's find f(2)f(2):

f(x)

f(2)

​    

=x+1

=2+1

=3

​  

now, let's find g(2)g(2):

g(x)

g(2)

​    

=2x

=2⋅2

=4

​  

so f(2)+g(2)=3+4=\greend7f(2)+g(2)=3+4=7.

notice that substituting x =2x=2 directly into function hh and finding f(2) + g(2)f(2)+g(2) gave us the same answer!