Question

2) Calcule os zeros, ou raízes das seguintes funções do 1o grau:

a) y = 3x + 12
b) y = -10 +60x
c) y = -2x + 9
d) y = 7x -28
e) y = -35 +7x
f) y = -6x +18

Answer 1

a) y = 3x + 12

3x + 12 = 0

3x = 0 - 12

3x = - 12

x = - 12

---

3

x = - 4

b) y = - 10 + 60x

- 10 + 60x = 0

60x = 0 + 10

60x = 10

x = 10

----

60

x = 0,16

c) y = - 2x+ 9

- 2x + 9 = 0

- 2x = 0 - 9

- 2x = - 9 . (-1)

2x = 9

x = 9

---

2

x = 4,5

d) y = 7x - 28

7x - 28 = 0

7x = 0 + 28

7x = 28

x = 28

-----

7

x = 4

e) y = - 35 + 7x

- 35 + 7x = 0

7x = 0 + 35

7x = 35

x = 35

-----

7

x = 5

f) y = - 6x + 18

- 6x + 18 = 0

- 6x = 0 - 18

- 6x = - 18 . (-1)

6x = 18

x = 18

----

6

x = 3