– Determine o zero de cada função abaixo:
a) f(x) = 2x – 6
b) f(x) = 8x – 4
c) f(x) = 3x + 9
d) f(x) = -2x + 4
e) f(x) = 7x – 5
f) f(x) = 10x + 5
g) f(x) = x – 5
h) f(x) = - 6x – 2
i) f(x) = - 7x + 5
Respostas
Explicação passo-a-passo: sendo f(x) = 0 para todas as questões logo:
a) 0 = 2x – 6 ----> 2x = 6 ---> x = 6/2 -----> x = 3
b) 0 = 8x – 4 ----> 8x = 4---> x = 4/8 ----> x= 1/2
c) 0 = 3x + 9 -----> 3x = -9 -----> x= -9/3 ---> x = -3
d) 0 = -2x + 4 ---> 2x = 4 ----> x = 4/2 -----> x = 2
e) 0 = 7x – 5 ----> 7x = 5 -----> x = 5/7
f) 0= 10x + 5 ------> 10x = -5 -----> x = -5/10 ---> x= -1/2
g) 0= x – 5 ----> x = 5
h) 0= - 6x – 2 ----> 6x = -2 ----> x= -2/6 ----> x = -1/3
i) 0= - 7x + 5 ----> 7x = 5 -----> x = 5/7
Explicação passo-a-passo:
a) f(x) = 2x – 6
0=2x-6
0-2x=-6
-2x=-6(-1)
2x=6
x=6/2
x=3
b) f(x) = 8x – 4
0=8x-4
0-8x=-4
-8x=-4(-1)
8x=4
x=4÷4/8÷4
x=1/2
c) f(x) = 3x + 9
0=3x+9
0-3x=9
-3x=9
x=-9/3
x=-3
d) f(x) = -2x + 4
0=-2x+4
0+2x=4
2x=4
x=4/2
x=2
e) f(x) = 7x – 5
0=7x-5
0-7x=-5
-7x=-5(-1)
7x=5
x=5/7
f) f(x) = 10x + 5
0=10x+5
0-10x=5
-10x=5
x=-5÷5/10÷5
x=-1/2
g) f(x) = x – 5
0=x-5
0-x=5
-x=5(-1)
x=-5
h) f(x) = - 6x – 2
0=-6x-2
0+6x=-2
6x=-2
x=-2÷2/6÷2
x=-1/3
i) f(x) = - 7x + 5
0=-7x+5
0+7x=5
7x=5
x=5/7