Question

Determine a raiz das funções :
a) f(x)=-3x-6

b) f(x)=4x-1

c) f(x)=2x+2

d) y=x/4+1

e) y=-x/2-4

f) f)x)= -4x

Answer 1

a)
f(x) = - 3x - 6 
0 = - 3x - 6
3x = - 6
x = - 6/3
x = - 2
-------------------------
b)
f(x) = 4x - 1 
0 = 4x - 1
1 = 4x
4x = 1
x = 1/4
-----------------------------
c)
f(x) = 2x + 2
0 = 2x + 2 
- 2 = 2x
2x = - 2
x = -2/2
x = - 1
-----------------------
d)
 y=x/4 + 1 
0 =  x + 1
       4

mmc = 4

0 = x + 4
4       4

- 4 = x
x = - 4
-----------------------------------
e)
 y= - x/2 - 4
0 = - x  - 4
        2

mmc = 2

0 = - x - 8
2         2

0 = - x - 8
x = - 8
-------------------------------

f)
f (x)= - 4x
0 = - 4x
- 4x = 0 ( -1)
4x = 0
x = 0/4
x = 0