Question

me ajudem nesse exercício de matemática

Answer 1

a)

4.(x + 1) = 12
4x + 4 = 12
4x = 12 - 4
4x = 8
x = 8/4
x = 2

***********************************
b)

5.(3 - x) - 4x = 18
15 - 5x - 4x = 18
15 - 9x = 18
15 - 18 = 9x
- 3 = 9x
9x = - 3
x = - 3   (:3)
      ------
        9   (:3)

x = - 1
     ------
        3

*************************************
c)

9x - 3.(2x + 2) = 15
9x - 6x - 6 = 15
3x - 6 = 15
3x = 15 + 6
3x = 21
x = 21/3
x = 7

***************************************
d)
- 3.(x - 5) - 2.(2x + 1) = - 8
- 3x + 15 - 4x - 2 = - 8
- 7x + 13 = - 8
13 + 8 = 7x
21 = 7x
7x = 21
x = 21/7
x = 3

*******************************************

Figura: retângulo

2.5 + 2.(x + 1) = 38

a) (p = 38) perímetro do retângulo, ou seja, a soma dos lados.

b)

10 + 2x + 2 = 38
12 + 2x = 38
2x = 38 - 12
2x = 26
x = 26/2
x = 13

¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨
c) Área = x.y

x = lado 1: 5
y = lado 2: x + 1 = 13 + 1 = 14

a = x . y
a = 5 . 14
a = 70 u.a (unidades de área)

******************************************************